VOL. XXV.] FHILOSOPHICAL TRANSACTIONS. 36/ 



of them that were burst with heat into clean rain water; and after several hours 

 I poured it on a clean glass plate, that it might evaporate; which being done, 

 I discovered abundance of salts that were coagulated in rose-like figures of 

 several magnitudes, and all different. On another glass there were a great 

 number of salt particles coagulated in figures like branches and boughs of trees, 

 which was a very agreeable object. 



The pieces of pearl that came out of the glass, and had been thrown into 

 the water, were blackish; I then caused the water, in which those fragments 

 lay, to evaporate, and put them on such a strong fire, that they turned white 

 again; on throwing these again into clean rain water, many of these particles 

 separated from one another, and sunk to the bottom, in appearance like white 

 chalk. From this water a scum arose on the top, which was coagulated salts. 

 I took a drop of water, which was very clear, from under that scum, and put 

 it on a clean glass, and observed in the space of 2 minutes, that there was, as 

 it were, a new scum drawn over the said water. But the next day this water 

 was wholly evaporated, and where it had lain thickest, there was nothing to 

 be seen but a white matter, as it appeared to the naked eye, but in reality, 

 there was an incredible number of exceedingly small particles, which for the most 

 part were so strongly coagulated, that there could be no particular figure dis- 

 covered in them ; but where the water had lain thinner, there the salt particles 

 were coagulated in the form of boughs and branches of trees. 



Some of the particles of pearls being beaten small like powder, then mixed 

 with water, and boiled till two-thirds of the fluid were evaporated ; then some 

 drops of this fiuid evaporated on clean glass, left a white-like matter to the 

 naked eye, which the microscope showed to be very clear crystals of salt, which 

 were very soft and tender ; whereas those that resulted from the burnt pearls 

 were quite hard and inflexible. 



Now since we see, that notwithstanding the boiling of pearl powder in water, 

 very few salts are extracted from it ; yet we have reason to believe, that the 

 stomach and bowels have a much less power over the pearl . particles that are 

 given to the sick ; and as for what belongs to the salt particles, with which the 

 water is impregnated by burning the pearls, and which coagulate in the water, 

 like a petrefied matter, it is probable that those do rather harm than good to 

 our bodies; and the more, as the juices in the stomach and bowels do so co- 

 agulate the salts of our meat and drink, that few or none of them mix with 

 the blood, but are mostly discharged with the rest of the excrements ; and 

 those salt particles, which do not coagulate, we ought to consider as bad as 

 poison, and especially those which put our bowels into such a motion, as to 

 protrude the chyle too hastily : this is plainly seen in the sea-fishes, which 



