526 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[December 31, 1870. 
which cannot be expressed by any simple formula. 
It may be noticed, however, that it contains the ele¬ 
ments of two molecules of a metaborate, NaB0 2 , 
with boracic anhydride B 2 0 3 ; or, since it is probable 
that part of its water is constitutional, it may be 
represented as an acid metaborate with water of 
crystallization, 2 (NaB 0 2 HB 0 2 ) 9 PI 2 O. Normal 
boracic acid is H 3 B0 3 ; take from this the elements 
of water, H 2 0, and metaboracic acid remains. 
Borax presents a weak alkaline reaction with lit¬ 
mus paper. [§ A hot saturated solution when aci¬ 
dulated with any of the mineral acids lets fall as it 
cools a scaly crystalline deposit (boracic acid H 3 B0 3 ), 
the solution of which in spirit burns with a green 
flame. 
The boracic acid is produced thus:— 
Na 2 B 4 0 7 + H 2 S0 4 + 5 H 2 0 = Na 2 S0 4 + 4 H 3 B0 3 . 
Boracic acid is a very feeble acid, which decom¬ 
poses carbonates but slowly in the cold; it reacts 
with turmeric as alkalies do. Upon this fact is 
founded an excellent test for its detection. The 
borate is mixed with a slight excess of hydrochloric 
acid and a piece of turmeric paper dipped into the 
solution. Upon drying the paper it appears of a 
reddish-brown colour, which becomes blue on mois¬ 
tening it with weak potash. Boracic acid is em¬ 
ployed in the Pharmacopoeia as a test for turmeric 
powder in rhubarb. Borax neutralizes acids to the 
same extent as an amount of sodic hydrate or carbo¬ 
nate containing the same quantity of sodium. Thus 
Na 2 B 4 O 7 10 H 2 O will neutralize H 2 C 2 0 4 2H 2 0 ; half 
a gram-molecule, or 191 grams, will, therefore, neu¬ 
tralize 1000 cubic centimetres of the volumetric so¬ 
lution of oxalic acid. 
Bromum. — [§ A liquid non-metallic element ob¬ 
tained from sea-water and from some saline springs]; 
also, in small quantity from help, the ash of sea¬ 
weed. From whatever source it is obtained, the 
same principle is adopted hi its preparation. The 
liquids from which the most easily crystallizable 
salts have been removed are made to receive a cur¬ 
rent of chlorine gas. Chlorine lias a greater affinity 
for metals than that possessed by bromine, conse¬ 
quently upon such treatment the bromides present 
undergo decomposition and the bromine is set free. 
Thus if bromide of magnesium be the salt operated 
upon, as is usually the case, the reaction proceeds 
thus:— 
Mg Br 2 + Cl 2 = Mg Cl 2 + Br 2 . 
Excess of chlorine is to be avoided or it combines 
with the liberated bromine. The liquors wliicli are 
now brown are shaken up with ether, which dissolves 
out the bromine, and rising to the surface, carries it 
ivith it. Drawn oft* and shaken up with a solution 
of potash, the ether gives up the bromine to the 
potash, which, after it has been several times em¬ 
ployed in the same way, becomes finally saturated 
with bromine and neutralized. On evaporating to 
dryness the solution of bromide and bromate of po¬ 
tassium thus obtained, heating the residue to destroy 
traces of brominated organic compounds, and finally 
distilling the residual bromide of potassium with 
sulphuric acid and black oxide of manganese, bro¬ 
mine is found in the receiver. 
2 KBr + Mn 0 2 + 3H 2 S0 4 
= Br 2 + 2 KHSO, -f MnS0 4 + 2H 2 0. 
[§ Bromine is a dark brownish-red, very volatile 
liquid, with a strong and disagreeable odour. Its 
specific gravity is 2'966. Agitated with solution of 
soda in such proportion that the fluid remains very 
slightly alkaline, it forms a colourless liquid:— 
( 6 NaHO -j- 3Br 2 = 5NaBr -j- NaBr0 3 -f- 3H o 0), 
Bromide. Bromate. 
which, if coloured by the further addition of a small 
quantity of the bromine, does not become blue on 
the subsequent addition of a cold solution of starch.] 
This last test is intended to indicate that the bromine 
is free from iodine, but it is quite useless for this 
purpose, and founded in error. If iodine were present 
in a sample of bromine, the whole of it would be 
converted into iodate wdiicli would not be decom¬ 
posed by the addition of bromine. 
GNaHO + I Br 5 
= 5NaBr + NaI0 3 + 3H 2 0. 
To detect iodine in bromine, dissolve the sample 
in weak sulphurous acid, employed in such propor¬ 
tion as to produce a solution almost, but not quite, 
colourless. The whole of the bromine and part of 
the iodine will thus be converted into liydracids, a 
small quantity of the iodine remaining unchanged. 
Br 2 + H 2 0 -f S0 2 H 2 0 = 2 HBr + H,S0 4 , 
and— 
I 2 + H 2 0 + S0 2 H 2 0 = 2 HI + H 2 S0 4 . 
It can then be recognized by starch. 
The boiling-point of bromine is 145'4°, not 117° F>, 
as stated in the Pharmacopoeia. 
Bromine, in its chemical relations, stands inter¬ 
mediate between chlorine and iodine. Its atomic 
weight 80 is very nearly the mean of 35 ‘5 and 127, 
which are those of chlorine and iodine respectively. 
The crystalline form of the chloride, bromide, and 
iodide of any given metal is the same in nearly all 
cases. The elements themselves, though different in 
many characters, resemble each other closely in not 
a few. They all three form coloured vapours, with 
an odour which, when concentrated, is exceedingly 
irritating and corrosive, but when feeble, as when 
the vapour is diluted largely with air, reminds of the 
sea. Chlorine is a green gas, condensable to the 
liquid state ; bromine is a very volatile liquid form¬ 
ing a brown vapour; iodine a solid, but volatile and 
producing a purple vapour. Each combines when 
in the gaseous state with an equal volume of hy¬ 
drogen to form a colourless gas, which is very 
soluble in water, and forms a strongly acid solution. 
THE COMBINATIONS OF CARBONIC 
ANHYDRIDE WITH AMMONIA AND WATER. 
BY EDWARD DIVERS, M.D. 
(Concluded from page 507.) 
Products of the Distillation of Sal-Ammoniac with ChalJc , 
with Potassium Carbonate and with Sodium Carbonate . 
Sal-Ammoniac ivith ChalJc .—I have already stated the 
collective evidence showing that when ammonium car¬ 
bamate is volatilized, it is not converted into vapour of 
itself, but into a mixture of carbonic anhydride and am¬ 
monia. In the case of the carbonates of ammonium, the 
evidence of their decomposition into these gases and 
water when heated is still more conclusive, as some water 
is always obtained in the free state. The nature, there¬ 
fore, of the products obtained by distilling a mixture of 
sal-ammoniac and chalk depends upon the behaviour of 
