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Feijcival, of Manchestei'j published in the third volume of 

 Perciyal'S; Philosophical and Experimental Essays, in 1776, 

 detailing several experiments; from which he fairly con- 

 cludes, that the Doctor's enthusiastic hope, of dissolving 

 all calculi, in a solution of carbonic acid, must prove 

 groundless, from the very dift'erent nature of their compo- 

 nent parts, as ascertained by his own experiments. This 

 was placed beyond further doubt, by our own learned and 

 ingenious professor, Mr. William Higgins; who, in an ana- 

 lysis of ai calculus, • of which he gives an account, in his 

 comparative View of the Phlogistic and Antiphlogistic 

 Theories, (a work of singular merit for that period, to 

 which we will afterwards refer,) and published so far back 

 as 1789i enumerates the rhany various substances contained 

 in one specimen only. The researches of Austin, Lane, and 

 Brugnatelli, led to similar results. But to the learned and 

 accurate Dr. Wollaston we stand indebted, for the first clear 

 and distinct discrimination of the component parts of these 

 substances. _ In a paper, read to the Royal Society in the 

 year ]797> which would not discredit either a Bergman or a 

 Klaproth, he has most accurately demonstrated, both ana- 

 lytically and synthetically, the component parts of three 

 distinct species of calculi; namely, the fusible, as he terms 

 it, or the ammonico-magnesian phosphat of Fourcroy; the 

 mulberry, or Ox9.lt of lime kind; and boho eairthi calculus, 

 or phpsph^^t of lime; which, ^ithbthe mioiiwelli .known' to 

 up since the time of Scheele, left us then 'aicquainted with 

 the. four species, of calculi^; of most frequent occurrence. 

 lu.iiiuj Under 



