fi54 PHILOSOPHICAL TRANSACTIONS. [aNNO J 728. 



lixiviate salts, as oil of tartar, per deliq. See. it rises in a white curdle; but acid 

 saline liquors, as spirit of salt, nitre, &c. cause no alteration. 



A gallon and half of this water being evaporated to dryness, the remains 

 weighed 3 dr. ] scr. and IQgr. ; some parts of which were white, and shot into 

 striae like needles, and others into prisms. 



The neighbouring country is chiefly a strong clay; the quarries produce a 

 very hard stone, which seems to be a composition of shells closely cemented 

 and embodied together, and some marcasites which abound with sulphur; in 

 sinking deep pits, they throw up stones like iron ore, and covered with a shining 

 metallic substance, and serpentine stones, &c. and the ploughed fields abound 

 with stones resembling shells of the escallop and cockle kind, striated with 

 some astroites, which are all strong alkalies, and with aquafortis, or spirit of 

 nitre, raise a violent ebullition. 



Concerning the Causes of the Gout. By Sig. Michele Pinelli, N° 403, p. 49 1. 



An account is here given of some experiments made upon gouty concretions. 

 Having gotten from a very gouty person, who had died at Rome, about 3-1- oz. 

 of that tophaceous substance commonly found about the joints of persons 

 afflicted with gout; Sig. Pinelli took 6 glass bottles, and put lOgr. of the afore- 

 said substance into each. He then filled the 1st of these bottles with distilled 

 vinegar, the 2d with sp. of vitriol, the 3d with sp. of salt, the 4th with sp. 

 of sal ammoniac, the 5th with sp. of hartshorn, and the 6th with sp. of urine. 

 After 24 hours he found the aforesaid tophaceous matter totally dissolved in the 

 3 first bottles, which contained the acid spirits, but in the 3 others, which 

 he had filled with alkaline spirits, it remained entire and untouched, even for 

 some time after. From hence he concluded this tophaceous matter to be of an 

 alkaline nature, as it is the nature of acid spirits to dissolve such substances as 

 are either altogether alkaline, or composed in part of an alkali. And this also 

 he conceived to be the reason why the aforesaid tophaceous substance remained 

 entire in the bottles filled with alkaline spirits, both being of the same nature, 

 and consequently not to be dissolved by each other. 



But for further satisfaction, he took the remaining part of this tophaceous 

 matter, being about 3 oz. and put it into a small retort. Then having fixed a 

 recipient to it, he distilled it, according to the rules of art, by a gradual fire, 

 and obtained a spirit, with some few drops of oil, about 2 dr. of a caput mor- 

 tuum remaining in tlie retort. This spirit he found to be a perfect volatile 

 alkali, altogether of the same nature with that which is extracted from blood. 



