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Occurrence of Germanium
258
CURRENT TOPICS.
[J. V. I.
Biophysics of the Common F o w l . ~ H . H. MITCHELL and W. T. HAINES, of the Illinois Agricultural Experiment Station (Jour. Agric. Res., 1927, 34, 549-557), have determined that the critical temperature of the chicken has an average value of 62 ° F. This temperature is defined as the environmental temperature at and below which the heat production of the fasting resting animal will increase in order to prevent a lowering of the body temperature. The value for the chicken is based on thirty-six experiments with twelve Rhode Island Red hens, winter feathered birds, in an atmosphere of low humidity, an6 in an air current of approximately 3 litres per minute. MITCHELL and HAINES (Jour. Agric. Res., 1927, 34, 927-943) also determined the basal heat production or basal metabolism of twenty-eight non-laying hens, and found it to be 54.9 calories per day per kilogram of body-weight, and 703 calories per day per square metre of body surface. For nineteen mature cocks, the average values found were 55.7 and 806 calories, respectively. J.S.H. Fabrics and Sunburn.mKATHERINE HESS, J. O. HAMILTON', and MARGARET JUSTIN, Of the Kansas Agricultural Experiment Station (Jour. Agric. l~es., 1927, 35, 251-259), find that the protection from sunburn which is afforded the skin by fabrics depends primarily on the amount of interspace due to weave. However, the vegetable fibres, cotton and linen, transmit some of the rays which burn an6 tan, while the animal fibres, wool arld silk, absorb a larger portion of these rays. Therefore, silk and wool offer a higher coefficient of protection against the actinic rays than do cotton and linen. J.S.H. BEFORE Moseley had promulgated the idea of atomic nmnbers and had shown that there cannot be more than ninety-two elements unless an element heavier than uranium be found, it was easy to account for an unidentified spectral line in sun, star or nebula by attributing to some otherwise unknown element, such as nebulium. In Nature, Oct. 22, 1927, A. FOWLER, Imperial College of Science, remarks: " It is, of course, no longer permissible to sttppose the existence of hypothetical elements to account for the long-standing mysteries of nebular spectra, and we must accordingly regard the nebular lines as being produced by known elements under conditions of excitation which have not yet been imitated in the laboratory." G. F. S.
Occurrence of Germanium.mJAcoB PAPISH, F. M. BREWER, and DONALD A. HOLT, of Cornell University (Jour. Am. Chem. Soc., 1927, 49, 3o28-3o33), report the occurrence of germanium in traces in certain tin ores, and in appreciable traces (O.Ol3 to 0.033 per cent.) in certain varieties of the mineral enargite, a cuprous thioarsenate which is an ore of copper. J.S.H.
CURRENT TOPICS.
[J. V. I.
Biophysics of the Common F o w l . ~ H . H. MITCHELL and W. T. HAINES, of the Illinois Agricultural Experiment Station (Jour. Agric. Res., 1927, 34, 549-557), have determined that the critical temperature of the chicken has an average value of 62 ° F. This temperature is defined as the environmental temperature at and below which the heat production of the fasting resting animal will increase in order to prevent a lowering of the body temperature. The value for the chicken is based on thirty-six experiments with twelve Rhode Island Red hens, winter feathered birds, in an atmosphere of low humidity, an6 in an air current of approximately 3 litres per minute. MITCHELL and HAINES (Jour. Agric. Res., 1927, 34, 927-943) also determined the basal heat production or basal metabolism of twenty-eight non-laying hens, and found it to be 54.9 calories per day per kilogram of body-weight, and 703 calories per day per square metre of body surface. For nineteen mature cocks, the average values found were 55.7 and 806 calories, respectively. J.S.H. Fabrics and Sunburn.mKATHERINE HESS, J. O. HAMILTON', and MARGARET JUSTIN, Of the Kansas Agricultural Experiment Station (Jour. Agric. l~es., 1927, 35, 251-259), find that the protection from sunburn which is afforded the skin by fabrics depends primarily on the amount of interspace due to weave. However, the vegetable fibres, cotton and linen, transmit some of the rays which burn an6 tan, while the animal fibres, wool arld silk, absorb a larger portion of these rays. Therefore, silk and wool offer a higher coefficient of protection against the actinic rays than do cotton and linen. J.S.H. BEFORE Moseley had promulgated the idea of atomic nmnbers and had shown that there cannot be more than ninety-two elements unless an element heavier than uranium be found, it was easy to account for an unidentified spectral line in sun, star or nebula by attributing to some otherwise unknown element, such as nebulium. In Nature, Oct. 22, 1927, A. FOWLER, Imperial College of Science, remarks: " It is, of course, no longer permissible to sttppose the existence of hypothetical elements to account for the long-standing mysteries of nebular spectra, and we must accordingly regard the nebular lines as being produced by known elements under conditions of excitation which have not yet been imitated in the laboratory." G. F. S.
Occurrence of Germanium.mJAcoB PAPISH, F. M. BREWER, and DONALD A. HOLT, of Cornell University (Jour. Am. Chem. Soc., 1927, 49, 3o28-3o33), report the occurrence of germanium in traces in certain tin ores, and in appreciable traces (O.Ol3 to 0.033 per cent.) in certain varieties of the mineral enargite, a cuprous thioarsenate which is an ore of copper. J.S.H.