COMPOSITION OF SULPHATES* ]^3 



heaps; the benzoate, in shining stellar laminse: The cam- 

 phorate of lime has a slightly saline bitter taste, leaving a 

 calcareous taste behind : the bonzoate is sweet, and a little 

 earthy. 



The camphorate of lime exposed to heat furnishes an 

 aromatic oil, resembling that of rosemary in smell; no 

 crystallized substance passes over; and the camphorate does 

 not melt. 



If the benzoate of lime be treated in the same manner, 

 crystals of benzoic acid pass over into the receiver, with an 

 empyrcumatie oil having a smell of balsam of Peru ; and 

 the benzoate remaining in the retort becomes perfectly fluid. 



The camphorate of lime dissolves in five parts of water at • 

 a common temperature; while the benzoate requires twenty 

 parts. 



XVI. 



: Inquiry concerning the Means of Knowing the Proportions 

 of Acid and Potash, that enter into the Composition of 

 Sulphate of Alu mine, and of Sulphate, Nitrate, and Muriate 

 of Potash: by Mr. Curaudau, Prof, of Chemistry 

 applicable to the Arts, and Member of various Literary 

 Societies*, 



AN undertaking the present inquiry I had no intention Products of a 

 of verifying the experiments of those celebrated chemists, lar £ e aIum 

 who have endeavoured to ascertain the quantities of acid variance °with 

 and base, that enter into the composition of sulphate of the admitted 

 potash; I was merely desirous of knowing why the annual thesalt!° nS 

 results of the alum manufactory, that I have established at 

 Vaugirard, were very far from agreeing either with the 

 quantity of acid, or that of potash, which different analyses 

 indicate as contained in sulphate of potash and in alum. 

 For instance, when, instead of 31 parts of acid, the quan- 

 tity designated as entering into the composition of 100 

 parts of alum, 43 or 44 are required ; and, instead of ten 

 parts and half of potash, fifteen and half are required for 



• Journ. de Phys, vol. LXVII, p. 5. Read to the Imperial 

 Institute, April the 4th, 1S08. 



100 



