EXPERIMENTS TO PRODUCE SULPHATE OF SODA, &C. \\Q 



as muriate of foda, fhould be added to a fufficient quantity of Various cau- 

 water; without a fufficient quantity of water in a heated pan ^"Jj*^ 11 

 it will fufe into a mafs ; furtace being loft, the difficulty of m ent of falts. 

 folution is almoft inconceivable. 



Salts holding an abundance of water of cryflallization, as 

 fulphate of magnefia and fulphate of foda, (hould be dilfolved 

 by a gentle heat in their water of cryflallization, and what 

 further water may be required, fhould be then added. Salts 

 abounding in water of cryflallization, added to warm water, . . 



will conglomerate, the caloric is abforbed, and although a 

 fmall proportion of the fait is diffolved, the remainder is made 

 colder : it is governed by the fame law as operates on the fo- 

 lution of ice. The power of adding water evades a fuper- 

 abundant quantity of mother liquor, and enfures a quantity of 

 cryftals. 



To obtain the faline liquor white and pellucid, it mould not 

 remain long in the iron pans, not more than two hours. 



The firft liquor pumped from the pans fhould be equally 

 mixed with the laft liquor, to obtain regular cryftals in confi- 

 derable quantity. It is known that the under layers of faline 

 liquors are heavieft. 



Very light liquors afford the largeft moots or cryftals. Very 

 large cryftals appear opake, and are never of a good colour ; - 

 hence the necellity of breaking down to make many furfaces, 

 to be acted upon by light. 



Heavy inline liquors, holding Glauber falts, produce a quan- 

 tity of fait in a compound ftate of cryflallization. 



A faline liquor, of a proper weight, will give numerous cryf- 

 tals, long and narrow, and thefe will be found in fhape and 

 colour mod perfect. Such cryftals were formed by the power 

 of froft in the troughs and trays, acting upon hot faline liquor, 

 in the night. 



The darkejt nights produced the beft cryftals. Perhaps the Light not necef- 

 night was colder than the day. At any rate, the maxim of the far y to . the c p { - 

 neceffity of Jight towards cryflallization is doubtful in this in- f a | ts „ 

 ftance. Light is not neceffary to the cryflallization of fulphate 

 of foda. 



The necfcffity of air towards cryflallization, as fliewn by the Air is ncceflary. 

 ufual experiment of admitting air to a folution of fait in a veflel 

 which did not previoufly contain air, is frequently exemplified 

 the large way. Salts fometimes will not moot in a liquor 



covered 



