METEOKOLOGY. « 2d 



isolation of a jjroteolytie dias'tase from liarlcy malt, and some of its properties are 

 described. 



The influence of phosphates and other mineral substances on the proteo- 

 lytic diastase of malt, A. Fernbach and L. Hubert ( Comjyt. liend. uicad. Scl. 

 Park, 131 {i'MO), Xo. 4, J>P- -'93-395). 



METEOROLOGY. 



Atmospheric radiation, F. W. Very (17. S. Dept. Agr., Weafhrr 

 Bureau Bui. 0\ pp. 13 J^., fys. 23). — This paper gives the results of 

 investigations carried on during- the past 8 years to determine the 

 law of radiation as dependent upon pressure or density of the air. 

 The apparatus and methods used are described in detail, and the results 

 of studies of the influence of various conditions upon radiation are 

 reported. 



"The results of the present research prove that within moderate depths of only a 

 few meters the radiation of dry air, purified from carbon dioxid, increases quite uni- 

 formly with the depth; that the radiation of a 1-meter layer of purified air at 50° C. 

 and near atmospheric pressure (735 mm. ), as compared with one at 0° C, is 0.00068 

 radim, representing a transformation and transfer of thermal energy ot 0.(i0068 small 

 calories every vsecoud through each square centimeter of limiting surface; that the 

 radiation of a like depth of carboii dioxid at the same temperature is three and one- 

 half times that of air, or 0.00238 radinj, which is very nearly a maximum for this tem- 

 perature, further increase of the radiant depth being unattended liy a corresponding 

 addition of radiant energy, showing that equilibrium between radiation and emission 

 has been almost reached at this depth; that the radiation from a layer of steam 5 ft. 

 deep at one-sixth of atmospheric pressure is two and one-half times that from a like 

 body of dry air at temperatures near the boiling point of water, and eight-tenths of 

 the radiant emission from the black solid body; while for smaller depths the radiant 

 power of water vapor is relatively greater, a steam jet of small dimensions radiating 

 over four times as strongly as one of air, a ratio which would doubtless have been 

 considerably greater if the air had been perfectly dry. 



"There appears to be no reason to doubt that the radiation of a moderate depth 

 of homogeneous air at a given temperature depends on the ])roduct of the depth by 

 the density, and remains the same when depth and density vary inversely; but the 

 absorption of a given mass of aqueous vapor has been found to be smaller when dis- 

 tributed through a large volume of air than when concentrated. The phenomena are 

 conditioned by molecular relations. Reciprocal Aariation of depth and density does 

 not change the number of molecules which are engaged in the radiant transaction in 

 a homogeneous medium; but dilution by another substance involves a partition of 

 energy among molecules whose radiant and absorbent properties are dissimilar. 



"As an absorbent of terrestrial radiation aqueous vapor is very much more efficient 

 than any other atmospheric ingredient ; but as radiators when in large masses, the 

 substances which compose the atmosphere do not differ as widely as might be sup- 

 posed, and the position of chief radiant may be assumed in turn by either aqueous 

 vapor, carbon dioxid, or the permanent gases, according as the depths and tempera- 

 tures of the emissive and absorbent layers change. The depth of gas which gives 

 maximum radiation at short range is an insignificant quantity compared with atmos- 

 pheric dimensions, and radiation from either the atmosphere of the earth or the solar 

 chromosphere is a superficial phenomenon, even when the masses of heated gas 

 measure thousands of miles in thickness. The fineness of the chromospheric lines in 

 the solar spectrum, although the shifts of the Fraunhofer lines indicate pressures of 



