174 PHILOSOPHICAL TRANSACTIONS. [aNNO 1772. 



From Dr. Wood's account of this water, it is evident that this fetid vapour, or 

 at least the principles which form it, are volatile; for he says the water keeps 

 much better in open than in corked bottles. 



Each drop of a solution of the fossil, as well as of the vegetable alkali, occa- 

 sioned a thick white cloud, that fell to the bottom of the glass. And each drop 

 of a solution of silver in the nitrous acid gave a milky cloud. Syrup of violets 

 became green, and an infusion of galls occasioned no particular change of colour. 

 102 oz. 3 drs. and 1 scr. were put into a large stone basin, and set on a sand heat 

 to evaporate with a slow fire. As soon as the water was warm, it let drop a 

 light dark coloured earth, which gathered in small heaps at the bottom of the 

 basin; and during this time, the water threw up some air bubbles to its surface; 

 when it was evaporated to about a pint (lib.) it was taken off the fire, and 

 filtrated through paper: the coffin through which it passed, after being dried, 

 was found to have acquired 21 grs. of additional weight; though he could not 

 collect more than 3 grs. of a stone grey coloured earth, which proved to be of 

 the absorbent or calcarious kind, for it eftervesced with and dissolved in the 

 vitriolic acid ; the remaining additional weight of the coffin, he believes, depended 

 on some of the salts of the water being taken up by the spungy filtrating paper. 



After this, the water was again set on the sand heat, and evaporated till a 

 pellicle appeared on the surface ; and during the evaporation it threw up a great 

 number of air bubbles: after this, it was set in a cool place for 3 days, at the 

 end of which time there appeared a quantity of thin lamellae, mixed with a small 

 granulated salt, covered with a light coloured yellowish liquor ; these he separated, 

 and threw the liquor into filtrating paper; and by these operations he got 

 53i. grs. of a salt which tasted sharp and salt, besides what had been taken up by 

 the coffin, which had increased Qgrs. in weight more than he had got of salt. 

 This salt being put in a tea cup appeared next day white, and had contracted a 

 little moisture, but did not run per deliquium. 



The remaining water, which was no\C' a yellowish ley, was again evaporated to 

 a pellicle, and he separated a quantity of white salt in lamellae, which remained 

 moist, till it was set in a tea cup on the sand heat, and evaporated to dryness, 

 when it weighed l dr. and 14 grs.; this salt attracted more moisture than the 

 former, and seemed at first as if it would run soon per deliquium ; but the next 

 day it remained in the same state. 



As he imagined that both this, and the salt before separated, was mostly sea 

 salt mixed with a bittern and oily matter, which prevented the crystallization ; 

 he dissolved the whole of both in distilled water, and evaporated with a very slow 

 fire till a crystallization began to appear, and then set it in a cool place, and got 

 some large perfect crystals of sea salt ; and by repeating this several times, he 

 obtained a full drachm of perfect crystals, which diminished in their size as the 



