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Since 1947 the State of California has been conducting a soil‐vegetation survey—an inventory of the vegetative cover and underlying soils of the wild land areas of the state. This soil‐vegetation survey is a particularly remunerative source of much information on the physical factors that affect the business of ranching. Practical applications of this information are discussed herein; a review of specific cases illustrates the value of these surveys in range management planning and administration. These cases also demonstrate that soil‐vegetation surveys are a practical tool for both the rancher, and the range technician in public service or private enterprise. They are an extremely effective means of conveying information, and have a great potential for developing interest in, and an incentive for, better range management.

The technic of artificial insemination of insects offers a possible method for initiating or maintaining colonies of species which do not mate under laboratory conditions, and thus it may be possible to obtain a better understanding of their biology and permit the study of certain disease vectors. The technic might be applied to the study of the heredity of some species; it could be an aid to the taxonomist in the determination of species of questionable category.

THE total cross-sections for the scattering of fast neutrons of known energy by a number of light elements have recently been published1,2. The results for the elements carbon and oxygen show resonances at certain values of the neutron energy, and these resonances are ascribed to energy-levels in the compound nucleus formed in the scattering process. Similar resonances in (n,α) transmutations produced by fast neutrons have been known for some time3,4, but no case has yet been reported in which both the total neutron cross-section and the (n,α) transmutation cross-section for a given element have been shown to involve the same level of the compound nucleus. We have been able to demonstrate this in the case of beryllium, which when bombarded by fast neutrons can yield 6He in accordance with the reaction5

The New Age in Physics

Experiments directed towards improved stabilization of the characteristics of germanium alloy junction transistors have emphasized, in the past, the “environmental” phase of device reliability. The selection of the best possible atmosphere and the development of suitable envelopes for the transistor element were the primary objectives of this early work. A critical review- of investigations intended to reveal the effects of environment indicates, however, that suitable atmospheres and seals do not alone assure a reliable device performance. Further, these experiments suggest that additional improvements in device reliability may be derived by adjustments in the final surface treatment given the transistor immediately prior to envelope closure.

IN a recent study of the transmutation of a number of elements by deuterons1, the emission of three groups of protons from magnesium under deuteron bombardment was reported. These groups were assigned to particular isotopes by arguments based chiefly on the value of the energy released in similar reactions with other elements and on differences between the excitation functions of the groups. We have now been able to bombard separated isotopes, and the accompanying graph shows the proton groups observed from targets of magnesium-24, -25 and -26 deposited On stainless steel. The deuteron energy was 930 keV. as in the earlier experiments, and the protons were observed at right-angles to the incident beam. The three targets for which the results are shown in the figure were cut from larger areas on which the magnesium was deposited; but since the deposits were not uniform, the target thicknesses could not be accurately estimated. In the case of the magnesium-24 target, observation of the width of a (pγ) resonance-level suggested an equivalent thickness of about 10 keV.; the thickness of the magnesium-25 and -26 targets was unknown, and the relative intensities of the groups shown in the graph are therefore unlikely to be those which would be obtained from targets in the normal isotopic ratio of thickness.

THE Atomic Energy Research Establishment, Harwell, has recently produced a number of separated stable isotopes in milligram quantities. The availability of such isotopes has already enabled new nuclear reactions to be discovered, and old ones to be confirmed. In this and a later communication we wish to report on some work of this nature with boron and magnesium.

ON irradiating scandium (45Sc) with fast neutrons of energy ≤20 × 106e.v., Pool, Cork and Thornton1observed two positron-emitting radioactive isotopes of scandium of half-lives 52 hours (‘strong intensity’) and 4 hours (‘very strong intensity’) respectively. With neutrons of <10 × 106e.v., neither period could be observed. Previously Walke2had given the following assignment of radioactive isotopes of scandium: 44Sc (52 hours), 43Sc (4.0 ± 0.1 hours), 42Sc (4.1 ± 0.1 hours). These he attributed to the reactions: 39K(α,n)42Sc, 41K(α,n)44Sc, 40Ca(α,p)43Sc, 42Ca(d, n)43Sc and 43Ca(d, n)44Sc. Pool, Cork and Thornton suggested that the two periods which they observed were due to the formation of 44Sc and 43Sc resulting from the reactions and

High Sensitivity Counting Techniques

Kelsey and Clarke1have recently discussed the variation with temperature of the integral heat of sorption of water by wood (ΔH), and its bearing on the specific heat (cm) of wood containing m gm. of moisture per gm. of dry wood. Empirically, it is found that cmis greater than the specific heat (c) calculated from the specific heats and proportions of the components, assuming a simple mixture law2. This effect is not confined to cellulosic materials, but has been observed on starch3, gelatin4, dried foods5and other hygroscopic substances. The suggestion has previously been made5that the excess specific heat could be accounted for in terms of the change in ΔH with temperature (T); Kelsey and Clarke quote the appropriate thermodynamic equation as where cwis the specific heat of the water, and c0the specific heat of the dry wood. Putting cw= 1, and noting that then where Δc is the excess specific heat.

Recently an improved structure for the hermetically sealed version of the point contact transistor has been developed. Units employing this structure have met satisfactorily military shock, vibration, and centrifuge teds and have characteristics which enable them to undergo severe temperature cycling without significant changes in important device parameters. The “electrical” reliability of these devices as indicated by power and shelf aging tests which have extended to 6,000 hours duration is excellent.