640 EEPORT— 1888. 



TUESDAY, SEPTEMBER 11. 



The following Report and Papers were read : — 



1. Third Report of the Committee for investigating Isomeric Naphthalene 

 Derivatives. — See Reports, p. 96. 



2. Note on the Molecular Weight of Caoutchouc and other Colloids. 

 Bij Dr. J. H. Gladstone, F.E'.S., and W. Hibbeet, F.I.C. 



While investigating the chemical and physical properties of caoutchouc the 

 authors had endeavoured to determine by Eaoult's method its molecular weight 

 when dissolved in benzene. They found it to be extremely high, although the 

 numbers obtained for caoutchene and hevene (substances of the same ultimate com- 

 position) agreed fairly well with what might be anticipated from the formulpB 

 C,f,EIji; and OooHg.,. They had subsequently examined the aqueous solutions of 

 other colloid bodies, viz., gum arabic, caramel, albumen, and ferric hydrate, with 

 the result in each case that the molecular weight as determined by Eaoult's method 

 is very high. No great reliance was placed upon the actual figures obtained, but 

 they were sufficient to corroborate the conclusion arrived at by Graham long ago, 

 that ' the equivalent of a colloid appears to be always high.' 



3. On some new Silicon Compounds. 

 By Professor J. Emerson Reynolds, M.D., F.B.S. 



The following substances were exhibited and shortly described : — 



SiClBr, 



SiRr,(SCN,,H4% 

 SiBr,(SCN,n3C3HJs 

 SiBr,(SCN,Jl3C,TI,), 

 SiBr,(SCN;H,(C,H3),), 

 and 



Si(NHC,H,),. 



4. On some new Thiocarhamide Compounds. 

 By Professor J. Emeeson Reynolds, M.B., F.B.S. 



The following substances were exhibited and shortly described : — 



(H,N.,CS),H,NBr 

 (HjN:CS),n,NCl 

 (I],N:CS)^(CH3)H3NBr 

 (H,N."CS)3 (CH3)H3NC1 

 (H,N;CS);(CUi,),H.,NBr 

 (H.N.CS), (aHJjHNCl 



and the trithiocarbamide derivative 



(H,N,CS)3Br.C,H,Br. 



5. Proposed International Standards to control the Analysis of Iron 

 and Steel. By Professor J. W. Langlet. 



It is well known that the results of chemical analysis will differ slightly with the 

 methods employed and with the personal peculiarities of the operator. This latter 

 might be called the ' personal equation ' of the analyst. These causes of variation 

 become of great importance in all investigations where minute quantities of foreign 



