250 Dr. A. Macfadyen, J)r. (>. II. Morris, and Mr. ,S. ll>\vl;ui<l. 



Emission of Energy from liadio-uctive Substan 



The velocity of the ions produced by Rontgen and uranium radia- 

 tion in air has been shown to be the same. The ions are thus probably 

 the same, and it is a reasonable assumption that the same energy is 

 required in both cases to produce them. On this assumption the 

 energy radiated by the radio-active substances can be determined. 



The radio-active material was spread over a known area and the 

 maximum current produced between the parallel plates determined. 

 The number of ions produced, and consequently the energy to pro- 

 duce them, can be calculated. 



For a thick layer of uranium oxide (3 '6 grammes spread over a sur- 

 face of 38 cm.) the energy radiated into the gas for 1 sq. cm. of the 

 surface is 



10~ n calorie per second. 



This amount of energy would suffice to raise 1 c.c. of water 1 C. in 

 3000 years, assuming no loss of heat by radiation. From observa- 

 tions on the current due to a very thin layer of uranium oxide it is 

 shown that the energy radiated into the gas is not less than OO32 

 calorie per year for every gramme of the substance. 



The energy radiated from thorium and radium is also considered, 

 and the presence of the rays from radium deflected by a magnet is 

 taken into account. 



In the case of radium, which is 100,000 times more radio-active than 

 uranium, the emission of energy per gramme of the substance is not 

 less than 3000 calories per year. 



"On Expressed Yeast-cell Plasma (Buchner's ' Zyinase ')." By 

 ALLAN MACFADYEN, M.I)., G. HARRIS MORRIS, Ph.D., and 

 SYDNEY ROWLAND, M.A. Communicated by Sir HENRY E. 

 EOSCOE, F.R.S. Received June 19 Read June 21, 1900. 



(First communication.) 



Introduction. In 1897 a communication was published by Professor 

 E. Buchner* in which he described a method by means of which he 

 claimed to have isolated for the first time the active alcoholic ferment 

 from the yeast-cell and to have demonstrated its action upon fer- 

 mentable sugars. Since then Buchner, mainly in conjunction with 

 Rapp, has from time to time given an account of his further investiga- 

 tions in this direction, and these investigations are still in progress. 



1 'Berichte d. deutsch. Chcm. Ges.,' 1897, p. 117. Vide also succeeding papers, 

 18971900, ibid. 



