176 THE RESULT OF THREE 
Sulphuric acid 36’065 Water 48’390 
Total 9989-3 * 
The stalactitical bitter salt of Neusohal, 
in Bohemia, contains Magnesia 15-314, 
Oxide of cohalt 0*688, Oxide of copper 0*382, 
Protoxide of manganese 0*343, Protoxide 
of iron 0*092, Sulphuric acid 31*372, 
Water 51*700, Total, 99*891 f 
5. The substances which have been alrea- 
dy described are all derived from foreign 
localities. I now proceed to relate the facts 
which have been ascertained with respect to 
the hair salts of this country. 
Mr. Phillips subjected to examination the 
salt which proceeds from the decomposition 
of iron pyrites in the shale of the deserted , 
coal mines of Campsie and Hurlet, in the 
nighbourhood of Glasgow. He obtained 
Sulphuric acid. . . . 30*9 - 3*07 atoms. 
Protoxide of iron. . 20*7 - 2*3 ,, 
Alumina ...5*2 - 1*15 ,, 
Water 43*2 - 19*2 „ 
100*0 
The formula deduced from his analysis is 
2 / S. -f Al. 2 S. 4- 16| Aq.l: 
He repeated the analysis, and obtained 
the sulphuric acid in excess. 
The conclusions at which I have arrived, 
after making several careful analyses, are, 
that the substance is by no means a steady 
compound, as I have never obtained the same 
quantity of alumina, and have found that of the 
acid to vary considerably. That the latter is 
often in excess is evident, from the salt 
tasting sour in many instances, while at other 
times it is nearly tasteless. Mr. Phillips 
informs us that he found the proportion of 
alumina less, in a second trial which he 
made, than in his first analysis, although the 
difference was not so considerable as to in- 
duce him to repeat his experiments. 
The specimens which I examined were 
from Campsie, and consisted of silky, 
albestus-like threads mixed with pieces of 
shale and sulphate of iron, which were care- 
fully excluded before dissolving the salt. 
It is very soluble in water, and often pos- 
sesses a styptic taste, from the presence of 
minute portions of sulphate of iron ; 5 grs. 
introduced into a platinum crucible, and 
exposed to the heat of a spirit lamp, lost, 
without altering in colour, 2*13 grs. By an 
additional heat, which rendered the salt 
reddish, 0*03 disappeared. If we suppose 
that all the water was expelled in the first 
experiment, without decomposing the com- 
pound in any degree, we obtain a per centage 
of 42*6 ; by the second we have 43*6. 
* Poggendorff, Ann. xxxi. 142 t Ibid. 
I Annals of Philosophy, Second Series, v. 446. 
ANALYSIS OF HAIR SALT. 
The following table contains the result of 
three analyses of hair salt fi*om Campsie : 
Sulphu- 
ricAcid. 
Protox. 
of Iron. 
Alumi- 
na. 
Water. 
1. 
S2-925 
19-800 
2-500 
44-775 
2. 
28-6S5 
19-935 
2-850 
48-580 
S. 
33-580 
19.620 
8-200 
43-600 
Mean . . . 
31-713 
19- 785 
2-850 
45-651 
Atoms . . . 
6-34 
4-39 
1-26 
1 40-5 
In these experiments the composition is, | 
First. Second. Third. 
Sulphuric acid . . 6*5 . . 5*727 . . 6*71 atoms, i 
Protoxide of iron 4*4 .... 4*4 . . 4*35 ; 
Alumina 1*1 .. 1*26.. 1*42 ! 
Water 39*8 .. 43*18. . 38*75 \ 
To represent the composition by these [ 
analyses, we have the formulae respec- j; 
tively : — ji 
1.4/S. -i- A1.S2 + 36 Aq. il 
2. Si /S.4- Al. S. + 34f Aq. i 
3. 3/S.4-Al,S1^4.27i Aq. ij 
And, as expressing the mean, we may ij 
adopt i 
S. + Al. Sl§ -f 32 Aq. || 
Another specimen which had been pre- [; 
served in a phial for some years was also ji 
analyzed, and yielded. l| 
Sulphuric acid. . 35*600 - 2.37 atoms. i 
Protoxide of iron . 13*500 - 1* ,, 
Alumina 7*127 - 1*05 
Water 43*773 - 12*9 
Total 100*000 1 
Which may be considered equivalent j 
to/s. 4* Al. S. -4- 13 Aq. with a great 
excess of acid. The salt had a strongly 
acid taste. If we take the mean of this 
formula with those which precede, we obtain ! 
nearly. 
2 /S. 4-x\l. S. 4- 20 Aq. 
which is quite different from the result of j 
Phillips. I 
Of the three analyses contained in the ji 
table, the third, perhaps, approaches most 
nearly the mean composition of this sub- 
stance, as it corresponds with the first so i 
far as regards the acid and iron, and the i 
water is identical with the result obtained 
by direct experiment. | 
From these facts, then, it appears that , 
the hair salt of the coal strata varies in its ! 
composition. But this deduction is what 
we should have been inclined to draw, from j 
the consideration of various analyses by | 
different chemists, of specimens of similar 
salts from other localities, which affect the ! 
same form of crystallization, although con- ] 
sisting of totally different constituents. 
Thus sulphate of magnesia, sulphate of 
manganese, as well as sulphate of alumina 
and iron are found, we have [also seen in 
capillary crystals. 
