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Selected Articles. 
ART. XXXVI. — ON THE QUANTITY OF WATER CONTAINED IN 
CRYSTALLIZED BARYTES AND STRONTIA. By Richard Phillips, 
F. R. S. L. & E. &c., Lecturer on Chemistry at St. Thomas' Hospital. 
Dr. Dalton in his Chemical Philosophy (vol. i. p. 523.) 
states that he found that 80 grains of fresh crystallized 
barytes, dissolved in water and saturated with sulphuric acid, 
gave 36 grains of dried sulphate of barytes; and hence he 
infers, that in the crystals 20 atoms of water are united to 
one atom of barytes. On looking into chemical works I do 
not find that any other chemist has attempted to ascertain the 
quantity of water which these crystals contain ; indeed Dr. 
Dalton's statement is quoted by both Thomson and Turner, 
Not remembering any case in which a binary compound 
like barytes unites with so many as 20 equivalents of water, 
and as Dr. Dalton admits that his experience on the crystals 
of barytes has been limited, I was induced to repeat the ex- 
periment, in order to ascertain whether or not these crystals 
formed an exception to what appears to me to be a general 
rule. 
With this intention I decomposed some sulphate of barytes 
by heating it with charcoal, and dissolving the sulphuret of 
barium in water: the solution was heated with peroxide of 
copper, and filtered while hot. On cooling, crystals of barytes 
were plentifully obtained, which were dried, as well as they 
could be, by repeated pressure between folds of blotting-pa- 
per. One hundred parts of these crystals were supersatu* 
rated with muriatic acid, and the solution was decomposed 
by sulphuric acid: in one experiment 72.19 parts and in an- 
other 72.15 parts of sulphate of barytes were obtained, giving 
a mean of 72.17; now as 116 of sulphate of barytes contain 
76 of the earth, 72.17 parts contain 47.28 of barytes, which, 
deducted from 100, the crystals employed, leave 52.72 as the 
quantity of water which they contained. Now a compound of 
1 equivalent barytes 76 } . C" 45.8 ) . 
10 eqnivalents water 90 
give 
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