SCIEJJTIFIC SUMMARY. 
317 
Preparation of pure Bromides for medical purposes. — In the Arch. Pharm. 
(clxxxi. 216), Herr Faust describes the following method for the preparation 
of pure bromides : — Bromic sulphide is first prepared by mixing together 2 
parts of sulphur (fiower) and 24 of bromine ; this is added to calcic hydrate, 
suspended in water, when the following reaction takes place : 
2 S Bi’e + 8 Ga e = 6 Ga Br^ + 2 Ga B 0^ 
The filtrate is saturated with carbonic anhydride, concentrated, and mixed 
with twice its bulk of alcohol. After a few days the solution containing 
pure calcic bromide is filtered off from the calcic sulphate, and evaporated. 
From this salt any other bromide may be obtained by mutual decomposi- 
tion. 
A neio body from Chloride of Silicium. — It is reported that MM, Friedel 
and Ladenburg have found, that on passing the chloride of silicium through 
an empty porcelain tube heated to a temperature near that at which this 
substance fuses, and then distilling, a new substance less volatile than 
the chloride is obtained. By repeating the operation a great number of 
times with the more volatile portions, a notable amount of a liquid boiling 
above 70° is obtained. This product submitted to fractional distillation is 
easily separated into chloride of silicium and a liquid boiling between 
136° and 139°. Limpid and fiimiug in the air, this liquid bears great re- 
semblance to chloride of silicium ; it is likewise decomposed by water ener- 
getically. Analyses were made by introducing weighed bulbs, full of the 
liquid, into fiasks containing a certain quantity of water ; breaking the bulbs 
afterwards, almost the whole of the silica, when sufficient water was present, 
remfxined in solution. The acid liquid, saturated with ammonia, was evapo- 
rated on the water-bath ; the residue, dissolved in w*ater, and filtered gave 
on the one side silica mixed with the glass of the bulb, on the other a solu- 
tion in which the chlorine was determined. The numbers obtained lead to 
the formula Si 20 Clg, from which the new body is seen to be an oxychloride 
of silicium. 
The Absorption of Vapours by Charcoal. — Mr. John Hunter, of Belfast^ 
continues his enquiries on this subject. In the last paper sent to the Chemical 
Society, he states that he has demonstrated the degrees and condition of 
absorption of each of the following substances : Ethylamine, iodide of ethyl, 
acetate of methyl, oxalic ether, hydride of salicyl, salicylic acid, iodide of 
amyl, napthaline, camphor, nitro-benzol, bisulphide of carbon, alcohol, acetone, 
and methylic alcohol. 
The Quality of the Present and Future Water of London. — In an able 
summary of the results of a scientific investigation of the present water, and 
the water proposed to be supplied to Londoners by the various schemes 
now before the public. Professor Frankland states these nine conclusions : 
1. The present Avater supply of the metropolis is largely contaminated with 
sewage. Both analysis and statistics concur in the statement that each 
glass of Thames water taken from the river by the companies, contains one 
tea-spoonful of sewage. 2. Although this sewage is generally, to a great 
extent, oxidised before the delivery of the water in London, yet there is no 
guarantee whatsoever that all its noxious qualities are removed, because 
these noxious qualities are, in all probability, contained in the mechanically 
VOL. VII. jSO. XXVIII. Z 
