Mr. J. D. Smith oti the Hydrates of Baryies and Stroniia. 89 



The crystals of strontia having been rendered perfectly dry 

 in the same manner as the barytes, 30 grs. were dissolved in 

 hot water and precipitated by bicarbonate of potasli ; the weight 

 of the carbonate of strontia obtained was 17 grs. = J2 of 

 strontia: a second experiment conducted in a similar manner 

 afforded from 31-5 grs. 17-57 of carbonate =: 12-31 of 

 strontia. 



Strontia. Water. 



1st exp. 12 — 30 = 18 



2nd exp. 12-34 — 31*5 = 19'16 



24-34 : 37-16 : : 52 : 80, or almost ex- 



actly 9 eqs. water to 1 eq. of strontia. As the quantity of 

 carbonate of strontia obtained by you would indicate rather 

 more than 10 eqs. of water to 1 of strontia, I should imagine 

 that your adoption of 10 eqs. of water to 1 eq. of strontia 

 as the composition of the crystalline hydrate, may be traced 

 to the same cause as in the case of the crystallized barytes, 

 viz. dampness of the crystals employed. 



If crystallized strontia is exposed to the heat of boilino- 

 water, it readily parts with a portion of its water of crystalli- 

 zation, without undergoing the watery fusion, and falls to pow- 

 der. 21-6 grs. of this powder dissolved in water and precipi- 

 tated by bicarbonate of potash gave 26-06 of carbonate of 

 strontia; the experiment being repeated upon 20 grs., 24-34. 

 grs. of carbonate were obtained : these respectively afford 18-3 

 and 17-1 grs. of strontia, combined, the first with 3-3 grs. of 

 water = 21-6 grs., and the second with 2-9 of water = 20. 

 The mean of these experiments affords from 20-8 grs. of the 

 powder 17-7 of strontia, and 3-1 of water = 52 or 1 eq. of 

 strontia, and 9-1 or 1 eq. of water. 



When the crystallized hydrate of strontia is heated to red- 

 ness it first falls to powder, then fuses, and finally leaves a 

 white friable mass, which v/hen moistened with water evolves 

 heat similar to lime when slaked. 



41-22 grs. of the crystals heated to redness in a covered 

 platinum crucible left 16-58 grs., and this repeated on 64-2 

 grs. of the crystals left 24-72 grs. ; the mean of these two ex- 

 periments gave 32-1 grs. of water expelled from 52-7 grs. 

 of the crystals ; or from 133, the eq.of the crystallized hydrate, 

 81 or 9 eqs. of water driven off" by a red heat. The residue 

 on analysis proved to be anhydrous; for from 23-76 grs. of it, 

 1-16 grs. of insoluble matter, and 32-3 grs. of carl)onate were 

 obtained, which are equal to 22- 7 of strontia -f M6 of inso- 

 hible = to the weight originally taken. 



Those experiments show that by a red heat all the water 

 Third Scries. Vol.9. No. 52. Atig. 1836. L 



