Februaky 3, 1922] 



SCIENCE 



131 



it could not be subjected to more than mo- 

 mentary bombardments. If, on the other hand, 

 a salt of lithium was employed, it evolved gas 

 rather copiously so that these experiments like- 

 wise had to be intermittent. At the time these 

 experiments were made the writer did not have 

 at his disposal either an alkaline earth oxide 

 electrode nor a tungsten spiral to serve as 

 source of electrons. As a consequence the 

 pressure of gas in the bombardment tvibe had 

 to be maintained within rather narrow limits. 

 The procedure finally adopted as most satis- 

 factory under the existing conditions consisted 

 in introducing the requisite amount of oxygen 

 gas into the thoroughly' evacuated tube con- 

 taining the lithium, which was present as oxide, 

 and subsequently absorbing the oxygen in 

 heated copper. Small quantities of other gases 

 found to be present were absorbed by suit- 

 able reagents. The voltage then available, 

 which was obtained from a very large spark 

 coil, probably did not exceed 150,000 volts. 

 With a bombardment chamber so designed that 

 metallic lithium could be cooled bj' liquid air, 

 or other refrigerant, while being subjected to 

 a less concentrated beam of electrons from a 

 tungsten filament electrode, it is probable that 

 the bombardment could proceed indefinitely. 



As a result of these bombardments a small 

 unabsorbed residue showing strongly the spec- 

 trum of hydrogen always remained. Because 

 of the excessive difficulty of removing last 

 traces of water vapor from the surface of 

 glass, there is no good reason for supposing 

 that the hydrogen came from another source 

 than water liberated and decomposed as a re- 

 sult of the bombardment. On the other hand 

 it must be remarked that in view of the well 

 known masking effect which hydrogen pos- 



sesses over the development of the spectrum 

 of helium, small quantities of helium that 

 might have been present would not have been 

 detected. Means were not at hand for en- 

 tirely separating this hydrogen from any 

 helium and searching for the latter by itself. 



The purpose of this discussion is to suggest 

 that with improved and more powerful appara- 

 tus there would be considerable hope of pur- 

 suing them to some sort of a definite con- 

 clusion. 



For much advice in its design and for blow- 

 ing many of the more difficult parts of the 

 glassware of this apparatus, the writer was 

 under great obligation to Dr. Harold S. Booth. 



Ralph W. G. Wtckopp 

 Cahpoenia Institute 

 OP Technology 

 Pasadena, Cal. 



THE EFFECT OF SODIUM HYDRATE UPON 

 THE DIGESTIBILITY OF GRAIN HULLS 



NuMEKOUS experiments have been made dur- 

 ing the last few years, particularly by German 

 investigators, in attempts by various treat- 

 ments to render more digestible the straws of 

 the different cereals, legumes and cruciferte. 

 Among the methods employed for this purpose 

 may be mentioned (a) the heating of finely 

 ground straws under atmospheric pressure, 

 (b) the treating of the fine straw with 3% 

 and 7 per cent, of sodium hydrate under 5 

 atmospheres, ( c ) cooking the straw in open 

 kettles or cement ovens with 8 per cent, sodiiun 

 hydrate for 12 hours, and (d) the treating of 

 ground straw with cold sodium hydrate of 

 various strengths for different lengths of time. 

 The action of sodium hydrate as well as of 

 calcium hydrate has proved effective, and the 



*One sheep only. 



