96 
THE VOYAGE OF II.M.S. CHALLENGER. 
(No. 2S.) Bromine taken, Gl*21 mgrms. 
I Precip., 200 c.c. of silver solution, b l = 56-95 
Loss = 4-26 
(No. 29.) Bromine taken, G 1 *3 1 mgrms. 
I. Procip., 250c.c. of silver solution, 5, = 56-77 
Loss = 4 - 54 
Th decantate was precipitated with silver (the volume used was forgotten to be noted 
down) ; the precipitate was decomposed by means of zinc, water, and a few drops of 
sulj liurie acid ; and the liquid tested with chlorine water and chloroform, and the 
bromine estimated colorimetrically. The quantity found was about 4 mgrms. 
TIk-m; last two trials were very disappointing. They seemed to prove that although, 
as -h"wn by experiments Nos. 23 and 24, about $#ths of the bromine can be brought 
.1 >wn b\ means of about 2.‘H> of tin- silvi r solution, even this is possible only at the 
expense of a tedious succession of fractional precipitations, each of which occupies a 
whole day. The following serii ; of experiments was made with a view of seeing what 
.•an bo attained by two successive precipitations with large proportions of silver solution. 
In « aoh rase the bromine to lie determined was diffused throughout a litre of liquid 
containing 30 grins, of pure chloride of sodium : — 
(No. 45.) Bromine taken, 61*31 mgrms. 
I. Precip., 200 c.c. of silver solution, ^ = 56-77 
II. „ 300c.c. „ fc 2 = 1-26 
Total bromine found = R = 58 - 03. 
T ; ic second precipitate in this <-aw was dicomposed by zinc and very dilute sub 
phurir arid, the solution precipitated with 50 c.c. of silver, and this small precipitate 
chlorinated. 
(No. 46.) Bromine taken, 61*22 mgrms. 
I. Frecip., 200 c.c. of silver solution, 5^59'GG 
II. „ 300c.c. „ b 9 = 108 
(2nd precipitate manipulated as in 45.) 
B- 60-74 
(No. 47.) Bromine taken, G 1 *2 1 mgrms. 
I. I’rccip., 200 c.c. of silver solution, lost 
II. „ 200 c.c. „ ftj-2-88 
(2nd precipitate chlorinated os it was.) 
