358 Profs. J. Dewar and J. A. Fleming. On the Dielectric 



7. The condition of marked swelling of the lymphatic glands is 

 one of, if not indeed the most evident pathognomic feature of the 

 disease. The contagium exists as a primary infection in the lym- 

 phatic glands. 



8. A very mild attack of rinderpest, such as is produced by injection 

 of blood of greatly decreased virulence, does not convey absolute 

 immunity, this latter being produced in proportion to the severity of 

 the attack through which, the animal had passed primarily. An animal 

 seemingly affected may have a relapse of the disease, which may go on 

 to fatal issue or be mild in type, leading to recovery. Animals in 

 the latter case always acquire immunity of a high degree. 



" On the Dielectric Constants of certain Organic Bodies at and 

 below the Temperature of Liquid Air." By James Dewar, 

 M.A., LL.D., F.R.S., Fullerian Professor of Chemistry in 

 the Royal Institution, and J. A. Fleming, M.A., D.Sc., 

 F.R.S., Professor of Electrical Engineering in University 

 College, London. Received June 29, 1897. 



Continuing the researches on which we are engaged on the Dielec- 

 tric quality of matter at very low temperatures, we have examined a 

 number of organic bodies and measured their dielectric constants at 

 and above the temperature of liquid air. 



The apparatus and arrangements for effecting this measurement 

 are described in a former communication by us on the same subject.* 



The frequency of the reversals of the electromotive force used in 

 charging the condenser in the experiments here described was, as 

 before, 120. The condenser used was the gilt cone condenser 

 described in the communication mentioned. 



In another paperf we have given the results obtained by us on the 

 measurement of the dielectric constants of glycerine, ethylene di- 

 bromide, and nitrobenzol at very low temperatures, and shown that 

 in the case of glycerine the very high value of the dielectric constant 

 possessed by this body, above — 100° C, is reduced, on cooling to 

 — 185° C, to a value not far from 3*0. We have also shown that a 

 similar great reduction in the value of the dielectric constant takes 

 place in the case of ethyl alcohol when frozen at —185° C.J 



* See Fleming and Dewar, " On the Dielectric Constants of Certain Frozen 

 Electrolytes at and above the Temperature of Liquid Air," ' Roy. Soc. Proc.,' voL 

 61, p. 299. 



f See Fleming and Dewar, " On the Dielectric Constants of Ice, Glycerine, Ethyl- 

 ene Dibromide, and Nitrobenzol at and aboye the Temperature of Liquid Air," 

 ' Roy. Soc. Proc.,' vol. 61, p. 316. 



X See Dewar and Fleming, " Note on the Dielectric Constants of Ice and Alcohol 

 at very Low Temperatures," ' Roy. Soc. Proc.,' vol. 61, p. 2. 



