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SeElion 6tb. 

 S E L E N I T E. 



There are two ways of combining vitriolic acid with lime and 

 and fome other fubftances ; one by direB folution or addition of the 

 bafisunto perfed faturation, fo as no longer to difcolour the ufual 

 tefts, the other by precipitation from another menftiuum ; in this 

 laft method the bafis takes up an excefs of acid, which as it is 

 wafhed off in other purfuits occafions no miftake, though it does 



in this. The ift experiment in my laft paper I followed the ift 



method, in it I found that 439 grains of a mixture of 225 grains 

 of vitriolic acid whofe fp. grav. at 60° was 1,56^4. with 225 of 

 water, faturated 152 grains of marble which contained lat the 

 rate of 55 per cent.) 83,6 of lime. By the table it appears, that 

 the vitriolic acid before dilution contained 54,46 real acid, then 

 439 of the dilute acid contained 1 19,5 of real acid, confequently 

 83,6 of lime took up 1 19,5 of real vitriolic acid, therefore if the 

 compound of both were free from water, we fhould have its 

 weight equal 83,6 + 1 19,54 = 203,14 nearly, and 100 parts of it 



would contain 41,15 lime and 58,8+ of real acid. But unlefs 



the compound be expofed to a high heat this weight cannot be 

 expedled ; the refulting felenite will always retain a proportion of 

 water, varying with the degree of heat to which it was expofed, 

 and it is this that occafions the variety of determinations of the pro- 

 portion 



