428 PHILOSOPHICAL TRANSACTIONS. [aNNO 1708. 



and of such several figures, that it was impossible to describe theni ; some of 

 them were clear as crystal, and it was very pleasant to see so many several figures 

 of such different shapes and sizes, lying together in so narrow a compass, and 

 fine and shining as they were when surrounded with water : no less dark were 

 almost all of them when the water was evaporated, when they appeared as if 

 dissolved into a great many small particles, seemingly of a whitish substance. 

 At another time I fancied that I saw the watery part, which lay about those salt 

 particles, impregnated with abundance of other salts, much smaller than the 

 former, which in evaporating the water, were coagulated on the first mentioned 

 clear salts, and so obscured their shining. After some days, decanting the 

 water off the whitish matter, and pouring fresh upon it, I observed that there 

 were salt particles still coagulating on the superficies of the water, which were 

 extracted from the coral in vast numbers. From hence we may conclude, 

 that the hardness of the coral proceeds only from the great number of its fixed 

 salts. 



Now as the heat of the fire was sufficient to take away the redness of the 

 coral as soon as put into it, I laid three small pieces of coral on aquafortis, to 

 try whether that would have the same effect ; when immediately the air bubbles, 

 which came out of the coral, took up four times the space the aquafortis had 

 filled before, and the coral, by the great multitude of air bubbles that conti- 

 nually proceeded from it, some of which also adhered to it, was raised from 

 the bottom to the surface of the water ; yet the said water was not in the least 

 tinged with the red coral, but it became whitish, which was occasioned by all 

 those parts separated from the coral ; and when the aquafortis had no more 

 power to dissolve the coral, because I had poured only a very little upon it, the 

 said dissolved parts subsided to the bottom, and the superficies of the aquafortis 

 resumed its former clearness. After the aquafortis had stood about two hours 

 on the red coral, I took a little of the whitish matter that had sunk to the 

 bottom of the glass, and putting it on a clean glass plate, I discovered a vast 

 number of oblong particles, that seemed like very fine hairs. I took also some 

 of the upper part of the aquafortis, that was clear, and pouring it on a clean 

 glass, I likewise discovered in it a great many oblong particles, like the former ; 

 and on examining more strictly the white matter that had subsided to the bottom 

 of the glass, I found it consisted only of the slender particles above-mentioned, 

 some of which were longer than the rest. 



The aquafortis having not been sufficient to dissolve all the coral, I added a 

 little more to it, and then observed, that in a short time the remaining part of 

 the coral was dissolved, saving that a very few parts, which were composed of 

 much smaller, (or rather those smaller were again coagulated) floated on the 



