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Mr. F. D. Brown on the Physical [May 31 , 



themselves*, and on the alleged destruction of germs by merely drying 

 them, on hermetic sealing, and on the deportment of hermetically sealed 

 flasks exposed to the sun of the Alps, are introduced towards the end of 

 the memoir. 



Throughout these laborious researches I have been aided, with his 

 accustomed zeal and ability, by my excellent senior assistant, Mr. John 

 Cottrell. He has been worthily seconded by Mr. Erank Valter, and, in 

 an humbler but still effectual way, by William Card. 



May 31, 1877. 



Dr. J. D ALTON HOOKER, C.B., President, in the Chair. 



The Presents received were laid on the table, and thanks ordered for 

 them. 



The following Papers were read : — 



I. "The Physical Properties of Homologues and Isomers." By 

 Frederick D. Brown, B.Sc. Communicated by Henry E. 

 Armstrong, Ph.D., F.R.S., Sec. C.S., Professor of Chemistry 

 in the London Institution. Received April 23, 1877. 



Observations of the physical properties of chemical compounds have 

 been very numerous ; in many, however, the object aimed at has been 

 merely the definition of the substances in question, and the results lay 

 claim to no great accuracy. In others, data have been required for the 

 solution of purely physical problems, and but little attention has been 

 paid to the chemical nature of the substances employed. In compara- 

 tively few has equal importance been attached to both the physical and 

 chemical aspects of the question. 



If, then, we attempt to compare the physical properties of a series of 

 compounds presenting very similar chemical properties, w r e find that in 

 the case of one or two members of the series our knowledge is tolerably 



* By the excellent researches of Dallinger and Drysdale it has been proved that the 

 germs of Monads, as compared with the adult organisms, possess a power of resistance 

 to heat in the proportion of 11 to 6. 



