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An investigation is described concerning the effect of tipping perforations on the yield of a variety of smoke components. The degree of ventilation covered the 20-70 % range. Tipping ventilation reduces the amount of air drawn past the cone during the puff and thereby compresses the thermaI profile of the cone. The yield of gaseous smoke components which have unique precursors is a function of time-at-temperature conditions in and near the cone and the effect on the yield differs between precursors as the amount of air flow is varied. Compounds that depend on distillation or sublimation to get into mainstream smoke are much less affected by tipping ventilation, i.e., condensation of these materials onto smoke particles becomes more efficient as the air flow past the cone is reduced and less particulate smoke is produced

s of papers in the field of freshwater biology published in British journals in 1 954 BARBARA DOUGLAS, T. T. MACAN and JEAN C. MACKERETH The following journals have been scrutinized, some, indicated by (b) or (z), only by the botanist or the zoologists respectively . The contractions are those in World List of Scientific Publications (London: Butterworth) . Ann. appl . Biol.; Ann. Mag. nat. Hist . ; Biol. Rev .; Endeavour; Entomologist (z) ; Ent. Gaz . (z) ; Ent. mon. Mag. (z) ; Irish Nat . (b) ; Irish Nat. Y. (z) ; Y. Anim. Ecol.; J. Ecul.; J. exp. Biol . ; Y. exp. Bot . (b) ; J. gen. Microbiol. ; Y. Linn. Soc. (Bot.) & (Zool.); ,7. Mar. biol . Ass . U.K.; Y. R. micr. Soc .; J. Quekett. micr. Cl . ; Y. Soc. Brit. Ent . (z) ; Naturalist, Lond. (b) ; Nature, Lond.; New Phytol. (b) ; Northw . Nat.; Phil. Trans . ; Proc . R . ent. Soc. Lond . (z); Proc. R. Irish Acad . ; Proc. Linn. Soc. Lond.; Proc. roy. Soc . B .; Proc. roy. Soc. Edinb .; Quart . Y. micr. Sci.; Scot. Nat . (b); Trans. Brit. bryol . Soc. (b) ; Trans. Brit. mycol. Soc. (b) ; Trans. R. ent. Soc. Lond . (z) ; Trans . Norf. Norw. Nat. Soc .; Trans. roy. Soc. Edinb. (b) ; Trans. Soc. Brit . Ent . (z) ; also The Phycological Bulletin too recently founded to be in the World List . It is not always easy to decide whether a paper should be included, for, in the first place, the limits of fresh water itself in bogs and fens and estuaries is not always clear . We have not included reviews which do no more than make passing reference to one or two freshwater organisms, and we have had, therefore, to make arbitrary decisions about how much reference to how many organisms qualify an article for inclusion . We consider it undesirable to load the list with papers of little general interest for the sake of completeness, and accordingly local lists and records which may fill a hole in the known range of a species but do not extend it have been omitted . Only those physiological papers which deal with problems arising from life in fresh water

Ten sorts of cigarette paper with differing physical properties, made of the raw materials Iinen, sulphate cellulose and “viskose”, which had been impregnated with citrate, phosphate or nitrate, were examined. The cigarettes made from these, which all contained the same blend of tobacco, were 7.95 × 80 mm and had an average weight of 1.070 g at 11.5 % moisture, were compared with each other in taste and in laboratory tests. A variation of the surface weight between 20.5 g/m2 and 24.5 g/m2 had no noteworthy influence on the properties of the cigarette. For the impregnation of the paper citrate is more desirable than the other salts investigated. The cigarettes made with paper impregnated with citrate provide the best looking ash and were favoured by the smokers of the taste panel. Cigarettes made with paper impregnated with nitrate and phosphate are stronger and more mordant and, furthermore, they have a bitter “after taste”, except those made with “viskose” paper. As the porosity of the paper increases the totaI condensate amount decreases. The “smouldering speed” of the cigarette increases somewhat. The members of the taste panel in each case preferred the milder cigarettes with the more porous paper. Paper made from linen, the most usual raw material nowadays for making cigarette paper, was compared with sulphate cellulose and “viskose” paper. Paper of sulphate cellulose is by comparison not very porous and gives the cigarette's taste tart qualities. “Viskose”, on the other hand, can be used to make very porous paper, the physical qualities of which come up to or even exceed those of linen paper. It was not possible to prove by the tests whether “viskose” paper negatively influences the taste of the cigarettes.

The present paper shows and discusses microphotographs of fibres used for the manufacture of cigarette papers as well as such photographs disclosing the composition of cigarette papers.

The influence of air permeability of cigarette paper on the yield of condensate and on its composition was examined. Total particulate matter and nicotine in the smoke decrease with increasing permeability of the paper. The decrease results from the smaller quantity of tobacco burnt in the mainstream. Higher combustion cannot be obtained by paper of greater permeability. The content of condensate of 3,4-benzopyrene is constant. Total particulate matter and nicotine in the smoke - measured in per cent of the tobacco smoked in the mainstream - are also constant.

WE have recently developed a simple method for quantitative assay of amino-acids on the paper partition chromatogram. The method is in all probability applicable to any class of substance which can be readily located by means of a sensitive colourreaction on paper. Several technical points of general interest have arisen in the course of the work.

Although this paper will not entirely neglect other tillage implements, the main interest is in mouldboard ploughs, and the detailed arguments presented will revolve about them. Nevertheless, the principles behind these arguments will have wider applications and, to this extent, it is hoped that the paper will be of general interest.

There is a proportional dependence between pressure difference and air stream of porous cigarette papers. In the case of perforated papers, however, the said relationship conforms to a non-linear function. It is therefore important to measure the permeability to air of these papers under a pressure difference that corresponds to the actual pressure conditions in cigarettes, i.e. approximately 0.25 dm water column gauge. With identical air permeability and identical degree of ventilation the yields of condensate, nicotine and phenols in the mainstream smoke of cigarettes made with porous paper decrease to a larger extent than the yields of the mentioned substances in the mainstream smoke of cigarettes made with perforated paper.

In addition to the comparison of the Gibbs negentropy ηG = ∫ Π ln Π to the Shannon negentropy ηs = ∑ EiΠi ln(EiΠi), discussed in the cited paper, a comparison of the former to ηs′=ηs−∑Ei lnEi the decrease in uncertainty, is of general interest from an information-theoretic standpoint. It is shown that ηG and ηs′ are similar in the situation in question. The additivity properties of ηG are briefly discussed.

New methods and the necessary equipment are described by which the porosity of relatively long strips of cigarette paper can be determined in a rapid and simple way. For the first time, the percentage of the total puff volume penetrating through the cigarette paper can be measured directly. The authors give several examples of application and at the same time they describe two new methods for determining the by-passing air.

This chapter discusses the papers presented by the House of Commons and the House of Lords. Whenever the House of Commons requires the submission of a report and orders it to be printed, the resultant document is issued in a numbered series of the House of Commons Papers. The series includes papers presented to both Houses and to the Commons alone. House of Commons Papers arise in different ways. Returns are printed in response to a direction of the House to obtain certain information. Act Papers comprise reports or accounts required to be laid before Parliament under the provision of certain Acts, though Act Papers of less general interest to Members are printed as Non-Parliamentary Publications, and others are simply laid open to inspection by Members in typescript form. Reports are made by select committees appointed by the House to inquire into special matters. The examination of witnesses is usually recorded in Minutes of Evidence, and papers submitted to a committee are usually published as appendices to its report. Minutes are printed of proceedings of standing committees appointed to examine Bills. House of Commons Papers are identified by their serial numbers, which are printed without brackets at the bottom left of their title pages. On the other hand, House of Lords Papers are distinguished by their serial numbers that are printed in curved brackets at the bottom left of their title pages.

Treatment of cigarette paper with ammonium sulfamate was found to cause changes in the composition of cigarette smoke, in the concentrations of components of both the gas and particulate phases. The concentrations of several polycyclic hydrocarbons were reduced by over 25 %, though benzo[a]pyrene was virtually unchanged. The concentrations of two nitrosamines were also reduced more than 25 %, while indole and skatole concentrations were reduced about 15 %. Among the gas phase components, acetaldehyde, acrolein and formaldehyde were reduced about 20 %; only carbon monoxide was moderately increased. Since these tests explored only small segments of the spectrum of cigarette smoke components, it is not known which of the observed reductions, if any, contributed to the reduction of biological activity of the smoke of treated cigarettes reported by Bock et al. (8). The tests indicate only that the nature of the smoke has been modified in several respects. The tar and nicotine yield of the treated cigarette was higher than that of the control cigarette, but this can be compensated for by reducing the diameter or length of tobacco rod available to be smoked

1. Air permeability1.1 Porosity1.2 Perforation2. Coefficient o fair permability oft he paper3. Degree of ventilation of cigarettes

The ''porosity'' or ''air permeability'' of cigarette tissue is measured by many different instruments, is expressed in various units and it is frequently impossible to correlate such measurements and the readings of such instruments. The property of a paper whereby it allows air and gases to pass through it while still containing the burning tobacco rod is of great and increasing interest in both the Research Laboratory and Raw Material Control Laboratory of the cigarette and filter rod manufacturer. Interest in papers of higher air permeability continues to grow, particularly in regard to the so-called ''Health Hazards of Smoking", and thus the effect of smoke dilution. Such interest by the cigarette and filter rod manufacturer necessarily means that the paper manufacturer must pay especial attention to this property during paper manufacture and in development work. He also requires to define and measure the property in his control and research laboratories. Unfortunately, there is no common language to describe this property and as interest in higher porosities grows so the shortcomings of some methods of measurement are highlighted. The situation is further complicated by the need of control laboratories for robust, simple to operate instruments, while a research laboratory might be more interested in accuracy and precision, while being less affected by the demands of careful operation and manipulation. Likely sample sizes can also vary, from small spills cut from individual cigarettes or rods, through long narrow skeins to the papermakers' sheets. A standard definition of air permeability of a sheet of paper has therefore been proposed and an instrument has been designed, using this definition, to meet the requirements of all interested parties. A number of these instruments have been built and proved by practical usage

The purpose of this investigation was to attain a better understanding of the selective removal of certain compounds from cigarette smoke by filters. A gas chromatographic method for the determination of selected semivolatile smoke compounds was developed. The method, which utilizes a 160 m glass capillary column, was used to determine the efficiency of filters for the removal of these selected semivolatile compounds. A correlation was found between the selective filtration of these compounds from cigarette smoke and their distribution coefficients [Kd = (g compound/g filter)/ (g compound/cm3 air)] between air and various filter materials. In addition, a correlation was found between the physicaI and chemical nature of certain smoke compounds and their selective filtration. Previous work indicated that if a compound is to be selectively removed from tobacco smoke by a filter, [1] a significant portion of that compound should be in the vapour state as it passes through the filter and [2] the compound should have an affinity for the filter material. The relative rate of vapourization (Rv) was used as a measure of 1., and the totaI solubility parameter (d) was taken as a measure of 2. Values for the vapourization rate were calculated from the product, vapour pressure (P), molecular weight (M), and diffusion coefficient (D), (Rv = kPMD1/2). The correlation of Rv and δ with the selectivity (Sx) of cellulose acetate filters for smoke compounds is described by Sx = b0 + b1δ + b2δ (1n Rv), where b0, b1, and b2 are constants. This equation may be used to predict the selective filtration of semivolatile compounds from cigarette smoke.

The authors studied the influence of tobacco moisture content on yield and composition of total particulate matter as well as on the temperature in the combustion zone of plain cigarettes. Total particulate matter and single components of the smoke can best be correlated with the dry weight of tobacco burnt in the mainstream. These figures are estimated by semi quantitative measures. The yield of dry total particulate matter is independent of tobacco moisture content if calculated on the basis mentioned above. The nicotine content of the smoke decreases with increasing moisture content of tobacco. Calculations on the where about of total nicotine suggest that nicotine is increasingly decomposed in the presence of moisture. The yield of 1,2- and 3,4-benzopyrene rises with increasing moisture content but with different slopes. The temperature of the combustion zone is independent of tobacco moisture content. The chemical and catalytic importance of moisture in smoking processes is mentioned.

A method for preparing cigarettes from ground tobacco is described and suggested as a simple means of comparing smoke yields of total particulate matter and nicotine. It is shown that yields from cigarettes made from ground and from cut tobacco are highly correlated.

PROTEIN tagged with radioactive iodine (iodine-131) is proving useful in immunological research because of its ready detectability1. Also the firm substitution of the iodine in the tyrosine molecule renders conclusions based on the occurrence of radioactivity in the tissues more acceptable as evidence of the presence of the antigen or its partial breakdown products than has been the case with arsenic and dye tracers2. The application of various methods including paper chromatography to the study of the fate of iodinated antigens has produced results which appear of general interest.

FIue-cured tobacco damaged by species of Aspergillus from commerciaI and experimental sources was shredded and made into cigarettes. Paired samples of nondamaged tobaccos served as controls. Subsamples of cigarettes were analysed for viable fungal propagules/g, 39 organic and inorganic compounds in the smoke and smoke condensates, and taste preference. PrincipaI fungi associated with leaves and shreds of mold-damaged tobacco were Aspergillus repens, A. ruber, and A. niger. Except for the originaI differences in the nicotine content and in the tar, there were no significant differences in total particulate matter nor in the amount of specific vapour phase components measured in the smoke from cigarettes made with mold-damaged and nondamaged tobaccos. Smoke panelists distinguished between cigarettes made with mold-damaged and nondamaged tobaccos and preferred cigarettes made with the latter. Viable fungus spores passed through the tobacco cylinder from lighted and nonlighted cigarettes. These data suggest the use of mold-damaged tobacco in cigarette manufacturing is to be avoided because of off-flavours and because the fungi isolated are common allergens to the respiratory tract of humans

Pyrolytic products of commercial tobacco sheet, flue-cured tobacco leaf, and stems were compared. The yields of acids, bases, neutrals, and phenolics were determined. The neutrals were further characterized by chromatography in order to examine pyrolysis fractions corresponding to biologically active cigarette smoke fractions. Individual phenols, carboxylic acids, polynuclear aromatic hydrocarbons (PAH), and nicotine were determined for sheet and leaf pyrolyzate. Analyses of constituents of various pyrolyzate fractions indicated significantly lower amounts of phenols, PAH, and nicotine in sheet and stem pyrolyzates than in leaf pyrolyzates

WE have read with interest the letter of M. Lederer on the paper chromatography of the noble metals1, especially as it appeared so soon after our own communication2 on inorganic chromatography. We have been engaged in a general study of this subject for the past two years3, and our results will be published in detail separately. In view, however, of Dr. Lederer‘s letter and the general interest which has been aroused by our preliminary communications2,4, we give below some supplementary information which may be of value.

Mr. G. I. Taylor, F. R. S., and Miss C. F. Elam investigated recently the distortion of "single-crystal" aluminium bars during a tensile test. By purely geometrical measurements they found that certain planes exist in the test-piece which, during its extension, remain undistorted. That is to say, that any curve drawn on these planes keeps its shape. From these observations they concluded that the test-piece must have a lattice-structure extending through the bulk of the material, or, in other words, that these test-pieces are single crystals. Mr. Taylor asked the writer to investigate by means of X-rays whether the "undistorted" or slip-planes could be related with the crystal-planes of the material which is known to crystallize in a face-centered cubic lattice. The result of this investigation is given in the above-mentioned paper of Taylor and Elam. The present paper is meant to give an account of the experiments so far as the X-ray work is concerned. A few points will be discussed later on which are likely to be of a more general interest.

A ventilating filter for cigarettes has been developed which reduces the delivery of smoke constituents from the final two to three puffs. Since the normaI delivery for these three puffs can account for up to half the total particulate matter and nicotine delivered by the whole cigarette, usefuI reductions per cigarette can be produced. The ventilating filter consists of cellulose acetate tow wrapped in heat-shrinkable film and attached to a tobacco rod using perforated tipping paper. When the cigarette is smoked, the perforations remain closed by contact with the impermeable film until transfer of heat to the filter is sufficient to soften the filter tow and shrink the film. Ventilating air now enters the cigarette and reduces the smoke deliveries. The effectiveness of the ventilating filter is increased by using films which have a low shrink temperature, high shrink tension and a high degree of biaxiaI shrinkage. Increases in filter plasticiser level, tipping perforation area and puff volume improve the effectiveness of the ventilating filter but increases in cigarette paper porosity and tobacco butt length reduce the effectiveness

A technique for axial concentration measurements of several gas phase components of cigarette smoke during a two-second puff has been described. Gas concentration profiles constructed from these measurements were used to determine the axial order of the reactions which determine these concentrations. A one-dimensional model combustion reaction profile and a one-dimensional model coal temperature profile were presented. The diffusivities of several combustion gases through cigarette paper were calculated from the concentration data using the Owens-Reynolds model for the isothermal diffusion of gases through cigarette paper.

This paper was originally written as a Note for the Institute of Actuaries Students' Society on ‘N.C.D. Systems in Motor Insurance’. This topic was one of nineteen non-life topics on which Notes were requested by the Students' Society in 1973, a different member of the Society being responsible for each topic. The Notes were not expected to give the results of research work along previously unexplored lines. Rather, they were intended as a survey of existing knowledge in each subject—including references to any useful literature—which could be understood by and be of general interest to members of the profession who had little or no experience of non-life work.Following a request from the Manchester Actuarial Society, it was decided to revise and expand the original Note to make a paper more suited for discussion. No Claim Discount (N.C.D.) is one of the more controversial areas of motor insurance, being a topic on which the motorist is liable to hold strong and emotive views from time to time. As now written the paper takes a critical look at N.C.D. systems, as well as outlining their basic features.

The contents of this paper were originally prepared for a contribution to a conference on ‘Design of commercial vehicle cabs in relation to the driver's environment’, held on 26th April 1973. The information contained in the address by the author was considered of general interest and value to the commercial-vehicle industry. The paper is aimed at providing guidance in the derivation of commercial-vehicle cab design with particular reference to packaging, accessibility and visibility. Certain conflicting requirements, design problems and solutions are discussed and the author's observations on some of the possible future trends in cab design are included.

Cholesterol-4-14C and b-sitosterol-4-14C were incorporated into cigarettes and their presence in mainstream smoke was studied. The transfer of 14C-labelled cholesterol to mainstream smoke was 20.27 %, of which 16.25 % was in trapped smoke condensates and 4.02 % in butts; only 0.004 % was in ashes. The transfer of 14C-labelled b-sitosterol to mainstream smoke was 16.20 %, of which 13.11 % was in trapped smoke condensates and 3.09 % in butts; only 0.007 % was in ashes. The relative composition of free sterols, steryl esters, and bound glycosides in cigarette tobacco and in trapped smoke condensates was also studied. Fractions of free sterols and steryl glycosides were higher while fraction of esters was lower in trapped smoke condensates as compared to cigarette tobacco. Comparison of four individual sterols (cholesteroI, campesterol, stigmasterol and b-sitosterol) was studied in cigarette tobacco and cigarette smoke (smoke condensates, butts, wrapping papers from butts). A slight increase of cholesterol was noted in smoke condensates and wrapping papers from butts.

The distribution of the air flow through the porous wrapping of a cigarette is ν (λ, l) being the density of the air flow (cm3 sec-1 cm-1) on the paper wrapping at the position l if l is the length of the porous paper wrapping between the non-porous tip and the burning cone and l is the distance of the position in question from the non-porous tip. ν (λ, l) is given in air flow per cm rather than in air flow per cm2 because of the cylindrical shape of the cigarette. I denotes the total stream at the mouth piece, a is the specific conductivity to air flow of the paper wrapping, b is the specific resistance to air flow of the tobacco rod, RG is the resistance to air flow of the burning cone [compare (1)]. The formula is derived and discussed. The dependence of the distribution of the ventilation stream on the length l and on the resistance RG is demonstrated for the case of a formerly investigated cigarette rod (1). The gradient of ν (λ, l) is so that the density of the ventilation stream through the paper wrapping decreases almost linearly from its maximum at the tip to its minimum at the burning cone if the degree of ventilation is low, i.e. if the air flow I (λ, l) in the cigarette is not much higher at λ = 0 than at λ = l

1. Introduction .—This paper deals with the purity of tone of the sound produced by an ordinary Seebeck siren, and with the problem of designing a siren to produce a pure, or comparatively pure, tone. The results were obtained in the course of certain technical experiments on the location of air­craft by sound; they seem, however, to be of more general interest, as a source of sound giving a fairly pure tone of some intensity, whose frequency may be varied at will, is not easily obtainable. The results here described were obtained by the authors in the course of their work as technical officers of the Munitions Inventions Department, and are published by permission of the Department. The experiments were carried out at the Acoustical Besearch Section of the Department with the help of Major W. S. Tucker, R. E. The authors’ best thanks are due to Major Tucker and his staff for their assistance. The Seebeck siren, as described in books on sound, consists essentially of a revolving disc bored with holes, against which a stream of air is driven from a delivery pipe. The holes are equally spaced round a circle, and the pipe is fixed so that as the disc revolves the holes pass the mouth of the pipe in succession; when no hole is opposite the pipe the flow of air is partially or completely interrupted, and as a hole approaches and passes the flow of air waxes and wanes. When the disc is rotated sufficiently fast, a musical note is produced, whose frequency is equal to the number of holes passing the pipe per second.

On October 10, 11 and 13, 1952, there took place in Buenos Aires, the Second Session in microchemistry in Argentina. There were four sections. In the section of organic and biological micro-analysis 13 papers were presented, in the section of inorganic micro-analysis 10 papers were given, while in the section of applied microchemistry and ultramicroanalysis 7 papers were delivered and in the section of general aspects of microchemistry 6 papers were offered. The Meeting was well attended and faculty members of all the five universities in Argentina participated actively in the presentation of the papers, which aroused general interest and are a living example of the present day advances in the field of micro-chemistry in Argentina.

I. Introduction. One of the most singular and striking rocks in that region of Anglesey which lies to the south-east of the principal mass of Carboniferous rocks, is a bright red jasper. Though never in masses of large size, it is widely distributed, occurring in three distinct areas, which may be called the Newborough, the Pentraeth, and the Beaumaris areas. The character, mode of occurrence, and associations of this jasper throw much light on its origin; they are so remarkable, and present such singular analogies with those of groups of rocks which have lately been described in different parts of the world, as to be, I think, matter of general interest, as well as important to workers among the older rocks of Britain. The object, therefore, of this paper is to describe the rocks and their relations in the districts where they have escaped the effects of the movements that have modified most of the region. Their geological age, and, in particular, their relations to the crystalline schists of the region, cannot, in my opinion, be regarded as settled, some of the evidence being conflicting. But as questions of the greatest interest regarding metamorphism are involved, I propose, in the fourth part of this paper, to set forth this evidence as briefly as is consistent with clearness. I am the less unwilling to do so, because the problem is so closely allied in its nature to those that are still under discussion at the margins of several other metamorphic areas

Session of Monday, December 28 No special meeting of the Society was scheduled for this day, and the members met in general session, with the Geological Society of America, in Sterling Laboratory, to hear the geological papers of general interest. In the evening our members listened to the address on “Geological climates” by Prof. Wm. B. Scott, the retiring President of the Geological Society of America. Following this address they participated in the complimentary smoker given by Yale University, in Byers Memorial Hall, to the Geological Society of America and its affiliated societies. Session of Tuesday, December 29 At 9 a. m. the Society met in joint session with the Geological Society of America for the reading of papers on stratigraphic geology. STRATIGRAPHIC PAPERS PRESENTED IN JOINT SESSION WITH GEOLOGICAL SOCIETY OF AMERICA PRE-CAMBRIAN AND PALEOZOIC GEOLOGY OF FORTUNE BAY, NEW FOUNDLAND BY NELSON D. DALE This paper was read . . .

The scheme of National Health Insurance, apart from its general interest to the student of social questions, presents many technical features of special interest to the actuary, and it has been suggested that the completion of the first valuations of approved societies, i.e., the societies administering the monetary benefits of the system, affords an opportunity for discussion of the scientific problems to which these features give rise. With the Government Actuary's consent, I therefore submit in the following paper an examination of some of the more important points of actuarial interest which have emerged in the course of the valuation work. Before approaching the main theme of the paper, however, I have described briefly certain factors, such as the principal alterations made in the financial structure of the scheme by the Act of 1918, a knowledge of which is essential to an understanding of the later part of the paper. These preliminary remarks are placed in Part I, the main subject being dealt with in Part II.

During the past few years a variety of applications have been found for the hot-cathode grid-controlled rectifier. In the present paper a general review is made of those industrial applications which are known to be economically possible. In order that the paper may be kept to a reasonable length and of general interest, a detailed account of the problems arising and results achieved with each application has not been attempted.A brief description of this rectifier (or thyratron) is given, together with some elementary principles which must be observed when designing circuits suitable for use with it. The grid circuit, especially, gives rise to problems and operating features probably not met with hitherto in industrial control apparatus.Though originally developed as a sensitive relay, the thyratron has now reached such a stage that it is able directly to control power of some magnitude, and thus has uses other than relaying.A Table is given showing the four main groups into which applications may be classified. Examples in each of these groups are dealt with briefly.The paper concludes with the disadvantages of thyratron control, and objections which have been raised to it. An answer can be found for most of the objections raised.

INTRODUCTION General interest in the Carolina Bays was aroused, in 1933, by the publication of a paper by Melton and Schriever,[1][1] in which they suggested that these features were formed by a shower of meteorites. During the past three years, members of the Department of Geology of the University of North Carolina have spent some time investigating these bays,[2][2] although only one major report has been published.[3][3] In that paper, Prouty summed up present knowledge concerning these puzzling features. He pointed out that: (1) The bays are found only on the Coastal Plain between the Savannah River and Norfolk, Virginia; they are most common near the North Carolina-South Carolina border. (2) Both bays and lake basins are elliptical, the major axes of the ellipses exhibiting a remarkable degree of parallelism. (3) The major axes of these ellipses all trend in a northwest-southeast direction despite the changing trends of the coast . . . [1]: #fn-1 [2]: #fn-2 [3]: #fn-3

This paper examines the machine utilization and job turnaround problems of a large computer center by analyzing the information handling and queuing problems occurring between jobs. A system designed to overcome these difficulties is described and the results of simulating the system are reported. The system design includes the interconnection of input-output computers with large scale processors by means of commonly shared disk files. Although this paper deals with a study which is not yet completed, the techniques developed and the results obtained to date are of general interest.

During the last twelve years I have communicated to this Society, often in collaboration with Dr. G. T. Prior, several papers descriptive of Bolivian minerals. These papers have dealt primarily with the species augelite, andorite, argyrodite, stannite, and chaleostibite, though many others have been examined and in some cases incidentally mentioned. The latter, as being of lesser general interest, or as not having led to sufficiently important results for separate publication, are now collected together in the present notes.

It is the purpose of this paper to bring to the attention of the chemical engineering profession a recently developed mathematical technique, called “linear programming”, which is exceedingly valuable in solving certain general problems connected with, inter alia, the efficient design of a chemical plant, and the discovery of an optimum production schedule which would maximize the profits of an enterprise. The general and more important features of linear programming will be discussed in the main body of this paper, while, in the Appendix, an illustrative problem of, it is hoped, general interest will be worked out numerically.

The construction and the development of the plough in Greece and Italy in ancient times is not a subject of general interest either to scholars or to archaeologists. It is, however, one which presents itself from time to time to students of Hesiod and of Virgil, and, since the obvious works of reference give but meagre aid to the enquirer, I have attempted to supply here a fuller account than is to be found elsewhere both of the literary and of the monumental evidence, in the hope that a more detailed discussion may not be without its uses.I propose in the first part of this paper to discuss and give a rough classification of the types of ancient plough which are represented on the monuments. In the second and third parts of the paper I shall attempt to sift the considerable number of ancient authorities who deal with the subject and to supply some comments suggested by the monumental evidence. The authorities, even when not directly concerned with Hesiod and Virgil, fall conveniently into line with the ancient commentators on those poets, and I shall deal first with Hesiod and then, more briefly, with Virgil.

HYPOPYON keratitis due to infection with the Gram-negative diplobacillus is an uncommon condition. Since the causative organism is of little general interest, bacteriologists have not studied it intensively. Ophthalmologists, on the other hand, find the organism very important but have given it little attention because of the special techniques required in its study. Petit,1in 1898, on the basis of his clinical and bacteriologic investigation of three cases, divided diplobacillary infections into two groups. Since then, ophthalmologists have considered central hypopyon keratitis to be due to the diplobacillus of Petit and marginal keratitis or conjunctivitis to be due to the Morax-Axenfeld bacillus (Moraxella lacunata). It is the purpose of this paper to demonstrate that this rather arbitrary division is not well founded on either clinical or bacteriologic grounds. HISTORICAL REVIEW In July, 1896, Morax2published the first paper on the Gram-negative diplobacillus. He described it as the causative

In his recent paper, ‘Newton’s Optical Aether’ (i), Professor Guerlac has uncovered much of interest in explanation of the format of the second English edition of the Opticks . That Newton intended that there should be a ‘Part II’ to the third book of the Opticks , seems now to be irrevocably proved, as also is the fact that the contents of this part were to include some of the electrostatic experiments of Hauksbee. It has previously been Professor Guerlac’s contention that these experiments of Hauksbee’s formed a distinct part in a revival of Newton’s belief in an aetherial medium (2), and in this recent paper he further suggests that for more, ‘persuasive experimental confirmation’ of the aether hypothesis, Newton devised the ‘two-thermometer experiment’ (3). I should like to suggest, and later in this paper to expound, that Newton’s interest in Hauksbee’s experiments, which were mostly performed between the years 1705-1712 (4), was related to a general interest in electrical phenomena and a specific interest in the attractive and repulsive forces exerted between the smallest particles of matter. Initially, however, there are other points which deserve of further consideration.

The following notes were compiled, for the most part, some years ago, but their publication in the present form suggested itself to the writer on the perusal (during a short “leave” from active service) of a number of recent papers ou Ammonites, principally Professor Swinnerton and A. E. Trueman's study of the “Morphology and Development of the Ammonite Septum”. The main part of that inquiry is devoted to the development of the septum, illustrated by successive “septal sections”, and it is claimed that where sutural development cannot be worked out, “septal sections” will to some extent serve as a substitute. The writer lias no intention of discussing the usefulness of “septal sections”; but some of the suggestions put forward, and conclusions arrived at, by the authors, as well as certain opinions, whicli they adopt from other workers on Ammonites, invite critical examination. Since, in the present paper, other recent work on the morphology and physiology of the Ammonite septum and suture-line, not yet embodied in textbooks, is also included, and since the writer ventures to put forward opinions that differ in many essentials from the views of both textbooks and other authors, it is hoped that the paper may prove of general interest.

According to the formulae the pressure drop R (l) and the degree of ventilation V (l) of cigarettes depend on the length l of the cigarette without tip, on the pressure drop RG of the incandescent zone alone, on the specific resistance to air flow b of the tobacco rod, on the specific conductivity a of the paper wrapping, and on the pressure drop RM of the ventilation-free cigarette tip. The parameters a and b are defined by the equations respectively, for the pressure drops RT and RP of the tobacco rod only and of the paper wrapping alone. In practice, the cigarette can approximately be considered as "ohmic" resistance to air flow, i.e. there is a linear relationship between pressure difference and flow rate. The degree of ventilation is the part of the total stream which penetrates the paper wrapping of the cigarette. The indicated relationships were theoretically deduced and empirically confirmed. The formula for R (l) corresponds to In general, there are the following relations where U1 is the total decrease of pressure occurring along both cigarette without tip and incandescent zone, I1 is the total stream leaving the cigarette at the cigarette tip, U2 is the decrease of pressure occurring along the incandescent zone, and I2 is the air stream which flows into the cigarette through the incandescent zone. The connections between U1, I1, U2, I2 and R, RG, V are as follows