COMPOUND POWDER OF ANTIMONY.
405
causes an orange red precipitate: if this be separated by filtering, andthe solution boiled to expel any traces of hydrosulphuric acid, a whiteprecipitate (phosphate of lime) is thrown down on the addition of causticammonia. That portion of antimonial powder which is not dissolved byhydrochloric acid is autimonious acid: if it be mixed with charcoal,and heated to redness, it is converted into sesquioxide, or metallicantimony.
Composition. — Dr. James's Powder has been analysed by Dr. Pearson{Phil. Trans, lxxxi. for 1791, p. 317); by Mr. Phillips {Ann. Phil. N. S.vi. 187); by Berzelius ( Traite de Chimie, iv. 481); by M. Pully {Ann. deChim. 1805, lv. 74); by Dr. D. Maclagan {Edinh. Med. Sury. Journ.xlix. 462); and was imperfectly examined by Mr. Chenevix {Phil. Trans.for 1801, p. 57). Antimonial poivder has been analysed by Mr. Phillips{Ann. Phil. N. S. iv. 266), and by Dr D. Maclagan {op. cit.) Theirresults are, for the most part, shown in the following table:—
JAMES’S POWDER.
ANTIMONIAL POWDER.
Pearson
Phillips
Berzel.
Maclagan
Fhillips
Maclatran
Antimonite of Lime [with}
Newbury’s
Newbury’s Butler’s
1st samp.
2 d do.
some superphosphate. 1
—
—
1
3-40
2-25
—
—
0-8
Maclagan] .(
..-57
56*0
06
2-89
980
—
—
3-98
Antimonious Acid.-
,43
42-2
33
43-47
34-21
35
38
50-09
Subpliosphate of Lime
• —
—
—
50-24
53-21
G5
62
4513
Loss [Sexqnioxide of AnO
timony and impurity, (
—
—
—
—
0-53
—
—
—
Phillips] .J
100
100-0
100
100-00
100-0
100
100
100*00
Pully found sulphate of potash and hypo-antimonitc of potash inJames’s powder. Mr. Braude has found as much as 5 per cent, of ses-quioxide of antimony in the antimonial powder of the shops.
The antimonite of lime is obtained in solution by boiling antimonialpowder in distilled w r ater: the greater part of it deposits as the solutioncools. The existence of superphosphate w-as inferred by Dr. Maclagan,from the precipitates produced with the salts of lead and nitrate of silver.Mr. Phillips assumed the non-existence of sesquioxide of antimony,because the hydrochloric solution did not let fall any precipitate on theaddition of water: an assumption which is certainly not correct, since asmall quantity of sesquioxide may be dissolved in this acid without ourbeing able to obtain any evidence of its presence by the action of water.Dr. Maclagan {op. cit.) has shown, that if hydrosulphuric acid gas betransmitted through the solution, an orange red precipitate is obtained,which he supposes to be an indication of the presence of sesquioxide.But unless the antimonial powder be boiled repeatedly in water, toremove completely the antimonite of lime, this test cannot be relied on:for if the least trace of this salt be present, an hydrated hydrochlorateof antimonious acid is obtained, which, it is w'ell known, not only pro-duces an orange red precipitate with hydrosulphuric acid, but evencauses a white precipitate on the addition of water (Gmelin, Handb. derChemie , ii. 986).
Physiological Effects. —Antimonial pow der is most unequal in itsoperation,—at one time possessing considerable activity, at another being-inert, or nearly so. This depends on the presence or absence of sesqui-