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An experiment to investigate the structure of the oceanic mixed layer was conducted between 28 September and 14 October, 1971, at 21N and between 66 and 67W aboard the NOAA Discoverer. During the experiment a quartz thermometer system capable of measuring temperature changes to within 0.001C was deployed from a surface buoy. Time-series temperature data were obtained from 10, 20, 30, 40 and 50 m depths and digitally recorded with a sampling interval of 1.1 min. This paper presents the results of an analysis of the temperature fluctuations in the mixed layer at selected levels for a three-day period characterized by fair weather conditions. STD measurements indicate there were no observable changes in salinity during this period. The observations show downward propagation of the diurnal heat wave at a rate of about 5 m hr−1 resulting in a turbulent exchange coefficient for the diurnal cycle of the order of 100 cm2 sec−1. During the heating portion of the cycle, which occurs during the day, the mix...

Measurements of air temperature with an immersion thermometer from an aircraft are invariably affected by the increased temperature of the decelerated air in the vicinity of the element. For dry air and a dry thermometer this effect is well known and usually taken into account. However, the evaporation of water from an element which has been wetted either intentionally (as in a wet-bulb thermometer) or unintentionally (by cloud or rain droplets) reduces this temperature increase. The psychrometric equation generalized for high-speed flow is used to calculate the aerodynamic correction factor for a wet temperature sensor. As an example of the magnitude of the evaporation effect, the temperature difference between a wet and a dry thermometer in a saturated airstream moving at 70 m sec−1>1C. Aircraft measurements in clouds from 3 different temperature sensors are discussed. The temperature differences between an exposed and a protected thermometer are found to be as large as 1C in conditions where t...

A low temperature Mossbauer thermometer suitable for the 25 to 250 mK temperature range with151Eu in EuS as the absorber has been discussed, and the problems of absorber thickness have been pointed out. The large correction for the apparent temperature deduced from the sum of Lorentzian analysis has been given for absorbers with a different number of resonance nuclei per cm2. With the correction procedure, without a least-squares fit using the transmission integral, one can obtain the temperature with an accuracy of better than ±2%.

A detailed re-examination of the temperature dependence of the optical properties of an aqueous solution of 3,5-dinitro salicylic acid is presented, which confirms the essential thermochromic nature of this solution. It is shown that the absorbance A of this solution, of strength 2.63*10-2 M measured at 520 nm, increases linearly with temperature over the range 10-45 degrees C. It therefore provides an optical method for measuring the temperature of any other system with which it is in thermal equilibrium.

Globe thermometers of various designs have been evaluated in a heated-wall wind funnel that provided a 98% complete radiation enclosure and a wide range of conditions of wind velocity and air temperature to represent extreme heat stress environments. Results showed that a good design for minimum time lag (the time required for the instrument to reach equilibrium) was a 6-inch diameter sphere having a 0.015-inch thick aluminum shell and either a miniature thermistor or a thermocouple as a sensor. Its time lag would be at the most, 10 minutes, whereas a globe thermometer using a liquid-in-glass thermometer would require 21 minutes. Convective heat transfer coefficients on 4-inch and 6-inch diameter spheres obtained by recent reseachers at wind velocities between 30 and 1000 fpm were used in the derivation of a straightforward expression for mean radiant temperature. This was employed to verify globe thermometer readings during tests over the full range of velocities and at radiant source temperatures (of th...

The behaviour of a typical cryogenic temperature control system is analysed in order to show which parts are critical for optimum performance. The most important single parameter is a very short thermometer response time, compared with all the other electrical and thermal response times in the system. The conclusions are illustrated by analogue computer results, and finally some practical comments are presented on how the optimum performance may be implemented in real systems.

A precision thermistor bridge and thermistor is described for use in a thermal titration calorimeter or a high-speed stopped- or continuous-flow calorimeter of the Roughton type. These are compared and evaluated with regard to several other types of detectors, including the platinum resistance thermometer, thermocouple, transistor thermometer, and capacitance thermometers. At this time the best detection for our purpose seems to be a specially constructed 20-100 kΩ thermistor used in conjunction with a new ac lock-in amplifier bridge. The sensitivity of the system is equivalent to a peak-to-peak noise of 25 x 10-6 °C, with a 100-ms time constant and 1 µW power dissipation in the thermistor. Long-term drift of the bridge, without an oven, was 1 x 10-6 °C/min.

The present authors have developed a rapid method for estimation of the difference between geothermal fluxes of two adjacent places, from surface temperatures and some meteorological parameters, based on a heat budget equation for simple vegetation-free ground surfaces. As this method requires simultaneous measurements of the surface temperatures at two places, an infrared radiation thermometer is the most suitable apparatus for this purpose. As an example, the distribution of the geothermal flux from a surface temperature field was estimated by scanning the Owakudani geothermal area, Hakone volcano, with the infrared radiation thermometer. The result was compared with the values of geothermal flux formerly determined by snowfall calorimetry, and it was shown that general patterns of the equi-heat-discharge line obtained by the two different methods are similar.

The types of resistance and diode thermometers in common use today are discussed and the sensitivities of the two different types of thermometer are compared.

The heat-conduction equation is solved for a simplified model of a scanning heat-conducting calorimeter with a working cell in the form of a spherical pyroelectric thermometer. The optimum material and dimensions for the pyroelectric sensors are determined by numerical analysis of the solution.

The magnetoresistance of 1/2 W, grade 1002, Speer carbonresistors with nominal room temperature resistances of 100, 200, and 470 Ω and of 1/8 W, 10 Ω, Allen‐Bradley resistors was measured at various temperatures between 0.5 K and 4.2 K in static magnetic fields up to 140 kG. In this temperature range the maximum magnetic field induced temperature error of these thermometers amounts to 14%. The Allen‐Bradley unit is to be preferred over the Speer resistors for use as a thermometer in a magnetic field for the following reasons: it has a more reproducible and regular magnetic field dependence, greater temperature sensitivity, and its much smaller physical size facilitates its incorporation in experimental apparatus where dimensions are restricted. One drawback of the 10 Ω Allen‐Bradley resistor is its relatively high impedance at the lowest temperatures. In addition, the effects of magnetic fields up to 150 kG on the characteristics of Chromel P/Au+0.07 at.% Fe and Chromel P/constantan (type E) thermocouples were determined in the temperature range 4.2–45 K. A description is given of the measuring apparatus along with a discussion of possible measurement errors and the necessary precautions which must be observed. The magnetic field induced temperature errors for the Chromel P/Au+0.07 at.% Fe thermocouples are relatively large at temperatures below 20 K, and are nonreproducible between sections of gold‐iron wire taken from the same lot. We do not recommend the use of these thermocouples below 20 K at fields greater than 50 kG. In contrast, Chromel P/constantan thermocouples have small, reproducible temperature errors up to 150 kG for 4.2≤T≤45 K. The data indicate that even in strong magnetic fields, at temperatures above 20 K, it is practical to correct for magnetic field induced temperature errors when using thermocouples. The reproducibility of the field induced errors in wires from different sources is still an open question and is worthy of further investigation.

A yaw sphere-thermometer assembly, to measure sensible heat flux density by the eddy correlation method, was built following the design of Tanner and Thurtell. Wind tunnel experiments indicate that the sphere constant should be 1.57, which is significantly less than the theoretical value of 2.25. The effects of tilt indicate that heat fluxes may be in error by 5% per degree of tilt In unstable conditions and up to 11% per degree in stable conditions. Field comparisons of the heat fluxes measured by the yaw sphere-thermometer system and a Bowen ratio apparatus produced satisfactory agreement. Copyright 1974 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC §108, as revised by P.L. 94-553) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a web site or in a searchable database, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. Additional details are provided in the AMS Copyright Policy, available on the AMS Web site located at (http://www.ametsoc.org/) or from the AMS at 617-227-2425 or copyright@ametsoc.org.

(1974). An overlooked autograph letter of Galileo on the thermometer. Annals of Science: Vol. 31, No. 5, pp. 457-462.

A thermometer has been constructed that is suitable for use in thermal gradient chambers. The water-proof sensing element is a forward-biased constant-current Schottky-junction hot-carrier diode. The voltage across the diode decreases with temperature in an approximately linear fashion and, with suitable corrections for the diode used, enables probe temperatures to be determined to within +or-0.05 degrees C over the range -65 to +50 degrees C.

After a general introduction, a number of practical considerations in the use of pulsed nuclear magnetic resonance for low temperature thermometry are discussed. A detailed description is given of a thermometer intended for use with copper samples at temperatures below 100 mK. Some experimental results are presented to confirm the reliability of a calibration procedure using Korringa's law and a determination of the spin-lattice relaxation time of the sample. Korringa's constant for copper has been measured using a 60 CoCo nuclear orientation thermometer. A value of 1.11 ± 0.02 sK was obtained in a magnetic field of 88 G. No temperature dependence was observed in the range 13–30 mK.

The earlier proposed noise correlation thermometer based on the compensation principle has been efficiently used in the regime of the periodic changes of the sample temperature. Registering the oscillations of the thermal noise and of the sample resistance allows to directly determine the temperature derivatives of the electrical resistance and of the heat transfer of the sample — the quantities necessary for calculating the temperature oscillations in the modulation measurements. The method has been checked on tungsten wire samples in the 800 to 2500 K range. [Russian Text Ignored].

This paper describes a 480 c/s a.c. bridge for comparing continously the resistance of two platinum resistance thermometers attached to the measuring and the reference parts respectively of a twin evaporated film adsorption calorimeter, and recording the difference between their resistances on a strip chart. The thermometer bridge output is amplified and synchronously detected. The resulting d.c. output actuates the amplifier of a 5 mv f.s.d. servomechanical recorder with two slidewires, the measuring and the retransmitting one. The thermometer bridge is continuously balanced by the retransmitting slidewire being a part of it. Thus the pen deflection is proportional to the temperature difference between the measuring and the reference parts of the calorimeter. The factors affecting the measurement of the temperature change of the measuring calorimeter are discussed quantitatively and compared with the case where the reference calorimeter thermometer is replaced by a fixed resistance. An expression is derived giving the optimum value of the bridge input voltage. The total gain is evaluated and the temperature record of a typical adsorption experiment is given.

An evaluation was made of the combined effects on airborne radiation thermometer (Art) readings in the 8–14 μm region of the emissivity of the water whose surface temperature is being measured, the infrared radiation from water vapor and carbon dioxide in the optical path, and the radiation reflected from the surface of the water. The water vapor and carbon dioxide in the optical path beneath the aircraft contributed 10–25% of the measured radiation; gaseous radiation reflected from the water contributed 0.1–0.6%. Radiation emitted from an overcast cloud layer (other than cirrus) and reflected from the water increased the Art reading by 0.5°C. The environmental adjustment reduced the root-mean-square difference between Art readings and a ship bucket thermometer from 1.7 to 0.6°C for 27 cases. A simple rapid graphic method based on the theoretical model was used on 51 cases at different aircraft heights and widely varying meteorologic conditions and produced a similar improvement.

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A sulphurous acid steam-pressure thermometer, on the plan described in my communication on the subject to the Royal Society of March 1, has been actually constructed, with range up to 25° C., but not yet in a permanent form.

Rhodium-plated kata thermometers were developed, as rhodium is a more stable coating than silver. The rhodium-plated kata thermometers were tested in non-turbulent air streams at the National Physical Laboratory, Teddington. Formulae for estimating true air velocities from cooling rates of the kata thermometers are given. Accompanying graphs facilitate the calculation of velocities. Cooling of the instruments is not directly related to the square root of air speed at low velocities. From zero speed (still air) up to a velocity of 0.5 m/s, plotting of cooling against velocity results in a parabola, and from 0.5-1.3 m/s in a straight line.

It is universally admitted, that, in the present advanced stage of Meteorological Science, nothing would be more desirable than complete and accurate registers of the indications of Meteorological Instruments,—more especially of the Thermometer, Barometer, and Hygrometer, such registers being cotemporaneously kept at numerous places, and at various elevations on the earth's surface. Many are the obstacles, however, which have been found opposed to such an acquisition.

The results of a heat flux comparison experiment carried out at Hay, New South Wales, Australia, during May 1966 using a sonic anemometer thermometer (SAT), Fluxatron and Evapotron are reported. The instruments agree with each other to within a factor of 2 for individual runs. The large fluctuations from run to run of the individual estimates are mainly caused by the fact that the Eulerian point average does not provide an adequate statistical sample of the heat flux. This point is illustrated by the non-stationary behavior of the instantaneous product of vertical wind and temperature. As auxiliary results, values of σw/u* and σT/T* have been obtained which are somewhat higher than, but in general agreement with, observations reported by Mordukhovich and Zwang.

The ``American Standards for Rotating Electrical Machinery'' (American Standards Association) prescribe that the temperature rise of motors shall be measured by the thermometer method for purposes of rating. Definite limiting values of temperature rise are established for each type of machine. The AIEE Standards No. 1 fix conventional allowances of 15 degrees centigrade, 10 degrees centigrade, and 5 degrees centigrade between the actual hottest-spot temperature and the highest observable value of temperature as determined by thermometer, resistance, and embedded-detector methods, respectively. This paper presents information on the relations between the measured values of temperature rise by different methods as found in tests on several hundred induction motors ranging from 10 to 1,000 horsepower in rating. It is shown that, with modern motor construction, variations of 20 degrees centigrade or more are sometimes obtained by the thermometer method on a given machine depending on location of thermometers or thermocouples, whereas the resistance measurements give relatively consistent values of temperature rise. It is therefore suggested that the standards for temperature-rise measurements be revised, and that the resistance method be adopted for all forms of enclosed or protected machines which are not readily accessible for application of thermometers on laminations, insulated windings, and other adjacent parts.

A general purpose instrument is described which is capable of providing temperature control to better than 1 mK for long periods in a wide variety of cryogenic applications. The main first and second order effects contributing to temperature instability are taken into consideration. For a range from 2 to 300 K at least two temperature sensing elements are required. The bridge circuit described is designed for use with an Allen-Bradley type carbon thermometer below 20 K and a copper or platinum thermometer above 20 K. Details of the circuit and constructional features of the controller are included.

A major microcalorimetric problem, the development of a very sensitive thermometer, is considered. The theory of a pyroelectric thermometer is reviewed and verified calorimetrically. A thermostatic system utilizing both a layer of low thermal diffusivity material and a large heat sink was used to strongly attenuate external temperature fluctuations. A pyroelectric thermometer, used in the thermostat, measured temperature changes as large as 2.52×10−3 °C and as small as 6×10−6 °C. The sensitivity of the thermometer was limited by the temperature stability of the thermostat. Technically simple modifications of the calorimeter could make the detection of temperature changes as small as 5×10−7 °C possible. Detection of temperature changes smaller than 10−7 °C may be achieved by changes in size, shape, and material of the pyroelectric sensing element.

Highest and lowest diurnal air and leaf temperatures in a corn canopy were compared with daily maximum and minimum temperatures in a standard thermometer shelter. Differences in temperature between canopy and shelter were related to general weather parameters. The main parameters governing the canopy-shelter differences in maximum temperature were insolation and time since the last rainfall. On bright, sunny days with low moisture, warmest leaves were 10°F (5.6°C) or more above shelter maxima, while air temperatures in the canopy were as much as 4°–6°F (2.2°–3.3°C) above shelter values. With lower insolation and/or recent rainfall, the differences decreased. Differences in minimum temperature between canopy and shelter were primarily a function of night-time radiation conditions. With atmospheric conditions favorable for radiational cooling, air minima were 2°–3°F (1.1°–1.7°C) below shelter minima, while lowest leaf temperatures were 4°–5°F (2.2°–2.8°C) below shelter values. When atmospheric moisture was high or overcast conditions existed the differences in minimum temperature between canopy and shelter were less. Tabular methods for estimating canopy-shelter temperature differences were developed, based on categories of the estimator parameters.

A great number of temperature measurements in deep bore-holes are made on the territory of the Soviet Union. The results of these measurements are partly systematized in the work " Problems of Geothermie " t1). However they can be hardly used for the calculations of heat flow because of the absence of the corresponding determinations of the thermal conductivity of rock cores taken directly from these boreholes. In the present paper the temperature gradient and the thermal conductivity of samples of rocks for the same place are determined and by means of these data the value of the thermal flow is estimated. For temperature measurements the electric resistance thermometer was used that is designed by Dergunov I. D. and improved for the conditions of work in deep bore-holes (up to 4-5 km) at rather high pressures and temperatures. The electrical resistance was measured by means of the compensation methods by a special potentiometer and a high sensitive mirror galvanometer. Four bringing wires are used for doing away with the erratic currents and the influence of the wires. As a result of it the accuracy of the temperature measurements is about 0.01°C. Fig. 1 represents the exterior of the apparatus and the thermometer. The thermometer is a hollow cylinder on the surface of which a copper wire is winded bifllarily, whose resistance is measured. When the cylinder is buried into a bore-hole it is washed by a solution from outside and inside. Together with the application of ftorplast isolation this decreases the thermal inertia of the thermometer down to 1.5 sec. For the sake of strength annular justs are made on the cylinder. The thermometer stands the pressure up to 600 atm and the temperature up to 200°C.

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Case 1.—S. E—, female. Admitted Jan. 22, 1866. Tried for wounding, with intent to murder, Dec, 1865. Found insane. She lived in a cellar with her husband and child. From the evidence given at the trial and from her own account, it appears that she wounded her child slightly with a razor in order to frighten her husband, who had treated her with great cruelty, into better behaviour. After she had been taken into custody it was found that “her mind was much shaken, and that she was the subject of delusions.”

It is just a century since James Six (the inventor of the well known Six’s registering thermometer) commenced some occasional comparisons of the temperature of the air at the top and bottom of the tower of Canterbury Cathedral. We do not precisely know the position in which the instruments were placed, and, as thermometer screens had not then been invented, his observations can only be accepted as approximately correct; but as the work in which they are recorded is rather scarce, it may be well to give an analysis of the results.

A simple experiment is described that permits advanced undergraduates to investigate the temperature dependence of electrical conductivity in copper wire down to liquid helium temperatures. At temperatures below 40° K the experimental results approach the T5 behavior expected from quantum mechanical calculations. At temperatures below 8° K a constant, nonvanishing resistance is found. The apparatus uses a nested Dewar system in conjunction with a helium gas thermometer.

The perovskite SrTiO3 can be controllably crystallized in situ in a glass matrix, and the resulting glass-ceramic displays a large peak in the dielectric constant at about 75 K (shifted from 35 K by doping and glass-chemistry techniques) and a T-1 increase in the dielectric constant below 0.1 K. This high degree of dielectric activity at cryogenic temperatures makes possible three potential applications: (1) A capacitance thermometer with a range from 0.1 to 70K which is unaffected by magnetic fields: (2) A 77 K capacitance energy-storage device; and (3) An adiabatic-depolarization cooling device below 0.1 K.Actual thermometers fabricated from this glass-ceramic (1 × 2 × 5 mm) had sensitivities ⋍ 250pF/K at 4.2 K and a linear C-T range from 1.1 to 5.2 K. It is demonstrated that this thermometer is unaffected by an intense magnetic field of 140 kG between 1.5 and 4.2 K.The field dependence of the dielectric constant at 77 K. was measured up to 180kV/cm, and these data were used to evaluate the Helmholtz en...

Paper thermometers that change, irreversibly, from white to black at a critical temperature were evaluated for measuring maximum surface temperature of dishes during commercial dishwashing in a single-tank, conveyor-type unit. A thermocouple, taped to a dish, was used to determine the maximum temperature attained at the surface of the dishes and this result was compared with a measurement obtained from a paper thermometer affixed to the dish. Temperature measurements by the two methods were within the 10 F span of the paper thermometer. Paper thermometers were found satisfactory for measuring the maximum temperature of the dish surface during dishwashing and also appear useful for routine checking of dishwasher performance.

The mean square Johnson noise currents flowing in a low-temperature seriesL–R circuit are used to measure absolute temperatures in a new method using an rf-biased superconducting magnetometer. In one set of experiments a quantitative study was made of the noise currents in a beryllium copper resistor located in the mixing chamber of a dilution refrigerator in the temperature range 5.4 mK to 4.2 K as a function of the magnetic temperature determined from measurements of the static magnetization of powdered CMN. In this temperature range the measured mean square noise current is found to be linearly proportional toT* with a coefficient which agrees within the experimental accuracy of±3 % with the theoretically predicted value based on the N yquist relation and independent measurements of all necessary calibration factors. A model for a SQUID operated in the flux-locked loop configuration with a partly resistive input circuit is presented and is used in the determination of the “device noise” temperature, which for the above experiment is found to be 0.16±0.02 mK. A calculation is presented of the length of time necessary to average the output of our thermometer in order to achieve any desired precision in the estimation of the mean square Johnson noise currents, and a comparison with the observed precision is made. In a second set of experiments the relationship between the Johnson noise temperature of a copper resistor and the 16-Hz magnetic temperature of two powdered paramagnetic salts, CMN and CDP, each in the shape of a right-circular cylinder with diameter equal to height, located in an adiabatic demagnetization cell, was determined from 2 to 20 mK. The device noise temperature characterizing the measuring system for these experiments was measured to be ∼0.05 mK. A discussion of the possible sources of inaccuracy associated with Johnson noise thermometry is presented. Particular attention is paid to the possibility of a heat leak directly to the noise resistor.

The method of Continuous Electrical Calorimetry, described in the following paper, was originally devised as part of a Fellowship Dissertation on applications of the platinum thermometer, at Trinity College, Cambridge, in the year 1886, but, on account of unforeseen difficulties, the experiments did not at that time get beyond the preliminary stage. In the first rough apparatus, a steady flow of water, passing through a tube about 30 centims. long and 3 millims. in diameter, was heated by an electric current in a fine spiral of platinum wire of about 5 ohms resistance, nearly fitting the tube. The steady difference of temperature between the inflow and the outflow was measured by a pair of delicate mercury thermometers, which it was of course intended to replace in the final apparatus by a differential pair of platinum thermometers. The electrical energy supplied was measured by the potentiometer method in terms of a set of 5 Clark cells and a large German-silver resistance of 5 ohms in series with the platinum spiral. The potentiometer was specially made for the work, and consisted of a metre slide-wire, and ten resistances, each equal to the slide-wire, for extending the scale so as to secure sufficient accuracy of reading. This potentiometer was still in existence at the Cavendish Laboratory in 1893. The set of 5 Clark cells were tested by Glazebrook and Skinner (‘Phil. Trans’. A, 1892), and were still in good condition at a later date. The external heatloss in these experiments was found to be much larger than had been anticipated, and so variable that the results were of little or no value. In order to remedy this defect, I designed the vacuum-jacket, which was suggested by some experiments of Sir William Crookes ('Roy. Soc. Proc.’, vol. 31, 1881, p. 239), which appeared to indicate that the rate of cooling of a mercury thermometer in a very good vacuum was ten to twenty times less than in air. I therefore regarded the vacuum-jacket as a most essential part of the experiment, and expected a great improvement to result from its use. Unfortunately I failed to make the jacket for want of sufficient skill in glass-work, and abandoned the experiment for the time, until my appointment as Professor of Physics at McGill College, Montreal, gave me greater facilities for carrying out the work. Eventually it proved that the effect of the vacuum-jacket in diminishing the external loss of heat was not nearly so great as I had been led to imagine, but it possessed several advantages as a heat insulator over such materials as cotton wool or flannel. The thermal capacity of a vacuum being negligible, the time required for attaining a steady state was much shortened. Moreover there was no risk of error from damp, which is the worst drawback of ordinary lagging. I had not originally intended to employ the electrical method for determining the variation of the specific heat of water, but only for comparing the electrical and thermal units at ordinary temperatures. In the meantime the work of Griffiths, with which I was intimately acquainted, had shown that the electrical units were probably in error, and appeared to indicate a smaller rate of variation of the specific heat than that given by Rowland. In reconsidering the problem, in 1893, I therefore determined to attempt the absolute measurement of the ohm and the Clark cell, in addition to the variation of the specific heat of water over as wide a range as possible. The method of steady-flow calorimetry appeared to be particularly adapted to the latter object, as it afforded much greater facility than that of Griffiths or Rowland in varying the conditions of experiment over a wide range. For the absolute measurement of the ohm, I immediately obtained estimates for a Lorenz apparatus of Professor V. J ones’ pattern, which was eventually ordered in October, 1894, and is briefly described in Section 6 of this paper. For the absolute measurement of the Clark cell in terms of the ohm, after spending some time in designing various forms of electrodynamometer, I decided to employ the British Association pattern, with certain modifications, which are explained below, Sections 10 to 16. At the same time I commenced a series of investigations into the defects of the form of Clark cell described in the Board of Trade Memorandum, in which I was assisted by Mr. H. T. Barnes. This work included an accurate determination of the variation of the E. M. F. with temperature and with strength of solution, in addition to measurements of the solubility of zinc sulphate and of the density of its solutions. It extended further than I had at first anticipated, and was not completed till the summer of 1896. The results were published in the ‘Proceedings of the Royal Society,’ vol. 62, pp. 117-152.

It is shown that it is possible to raise the recovery factor of a temperature-sensitive instrument (thermometer), located in a high speed gasflow, above one. Tests were run in this laboratory with such an instrument (thermocouple) in jets of air with both sub- and supersonic velocities. A design of the instrument is given.

Summary 1. 1. It is suggested that the results of Messrs. Finch and Cowen's experiments upon gaseous combustion and ignition in electric discharges might be explained equally well upon the thermal theory. 2. 2. Experiments made to test the accuracy of the two-probe method of' determining the electric force in glow discharges are described. These lead to the conclusion that above a pressure of about 2 mm. of mercury the method gives the electric force with an error of less than 1 per cent in discharges passing through air or hydrogen. The appearance of a peculiar isolated striation found in air discharges is described, and it is suggested that it is similar to that observed in hydrogen discharges by Prof. J. Zeleny. Graphs are given showing the distributions along the axis of a discharge-tube of the rise in temperature obtained by means of a platinum-wire thermometer and of the corresponding rate of dissipation of energy. It is found that the observed rise in temperature is not exactly proportional to, the...

The above semiconductor thermometer with a special transducer is convenient for measuring the temperature of flat, spherical, and fashioned outer and inner surfaces. The special transducer provides temperature measurements lasting not more than 10 sec. The error in measuring temperature does not exceed ±0.3°. The above technique for determining corrections of temperature deviations from the normal of the article and the measuring instrument by means of a semiconductor thermometer and special graphs raises the accuracy of measurement and productivity in manufacturing precision articles on metal-working machines, and reduces the percentage of rejects due to inaccurate measurements. The above technique and instrument can be used under workshop conditions at the bench, in the Technical Control Division (OTK), inspection and test points, in factory test laboratories, and in GKLs for measuring equipment of the State Committee of Standards, Measures, and Measuring Instruments of the USSR.

A radiometric device adapted to the measurement of temperatures of black surfaces is described. The precision of the instrument is such that surface temperatures may be measured to ±0.01°C. The apparatus has been used for the measuring of skin temperatures in humans. With the thermoelectric body thermometer, also described the, apparatus is ideal for studying thermal changes in the human body.

An approximate calibration of selected platinum resistance thermometers over the range from 2-27315°K can be obtained by using only calibrations at the boiling point of helium and the ice point and at temperatures between 2°K and 42°K as given by helium vapour pressure thermometer measurements. Interpolation between these points is achieved by employing a table of Z functions for the range 42-27315°K, and a polynomial equation in T against R for the range 2-16°K.

The magnetic dipole interaction between the nuclear magnetic momentu and the hyperfine fieldH hf in ferromagnetic metals leads to well-defined, evenly spaced nuclear energy levels which are accurately measurable by NMR techniques. When this is combined with the well-established anisotropic γ-ray emission properties of radioactive nuclei an excellent basis for absolute temperature measurement between 1 and 30 mK is obtained. Practical applications, however, require consideration of several experimental aspects. These are discussed in detail and graphs and tables are given in such a form that the data can be easily utilized. Experience gained with a nuclear orientation thermometer system employed in a nuclear refrigeration cryostat is discussed. A calibration of a pulsed copper NMR thermometer against a54MnNi nuclear orientation thermometer is presented.

For standard reference temperatures, samples of about 1 kg of pure metals are frozen and melted under carefully controlled conditions, temperatures being monitored by platinum resistance thermometry with a sensitivity of 0.1 mdeg. Solid is nucleated on the crucible wall, and slow freezing segregates impurities to the central axis, where a thermometer indicates the temperatures which are stable to 0.1 mdeg for 20 to 50% of the freezing time. Impurities segregate at different rates, and depress the freezing and melting temperatures by different amounts. During melting the heat flux inwards raises the outside temperature slightly above that of the centre. The impure centre melts first but the temperature rises rapidly until the outside reaches its solidus value, and also melts. The thermometer measures only the temperature of the inside interface, which melts slowly, driven by the difference in melting temperatures between the two interfaces. The melting temperature depression is the sum of the separate impurity depressions, and the complex melting curve is characteristic of the particular sample. Samples with impurities differing by 0.1 ppm can be distinguished with this technique, because impurities are concentrated by factors of up to 100 during freezing and the melting interface sweeps slowly through the impure zone.

Values of temperature in degrees C are conveniently derived from values of resistance of a platinum resistance thermometer by means of a table of temperature vs resistance. Since each thermometer has its own fundamental constants, it becomes laborious to prepare separate tables for different thermometers. This labor may be avoided by the method outlined. The method is to interpolate from a single ``standard'' table, applying corrections which have been worked out in a reasonably compact form to use the constants of each particular thermometer. A standard table and its correction table are given and were calculated by a rapid method which is outlined. A graph is the most convenient form for the corrections to this standard table. The procedure for making these corrections is discussed. In addition a graphical means of conversion is discussed, which is accurate to 0.01°C and is very convenient and rapid where this accuracy is adequate.

Cu doped with less than 1 ppm Mn54 appears to offer a number of advantages as a γ-ray anisotropy thermometer in the temperature range 1 to 20 mK. In order to use such a thermometer it is necessary to know how the hyperfine field at the Mn54 nuclei varies with temperature and with applied field. We have studied this γ-ray anisotropy and find that the hyperfine field is independent of temperature in the range 4 mK