( 280 ) 



be plcafihg to fome, I have omitted them, and the rather becaufr 

 1 meet with men, whole wliole aim is to find fault AVith what 1 

 advance. 



To thele oblervations i will add what I have obferved refpecling 

 Spanifli flies, or Cantharidcs. I have examined thefe Flies by the mi- 

 crolcope, and fo\md that their feet were covered with many won- 

 derfully fliarp particles; but, as thefe are feen on common flies, I 

 could not think that thefe particles could produce fuch an irritation 

 that when Cantharides are mixed with any ointment, and laid on 

 the body in the fliape of a plaller, they raife a blifter on the part. 



I put, therefore, fome Cantharides into a clean paper, and, hav- 

 ing pounded them, I poured clear rain water on them. Some of 

 this water I expofed to the air, that the faline particles in it might 

 coagulate, and, after about half an hour had elapfcd, I faw a very 

 great number of faline particles, which were three times longer than 

 broad, though I could not difcover their exaft fliape. 



I then took a larger quantity of water, and let it fl:and a whole 

 night, to fee whether thereby the faline particles would concrete in 

 larger figures. In this time almoft all the water was evaporated, 

 and the faline particles were fo concreted together, that I could very 

 dirtinAly difcover the fliapes of each of them. Thefe particles lay 

 in fuch numbers that they made the remainder of the liquid appear 

 white ; and it was a very pleafant fpeftacle to me, to fee fo many 

 particles lying together of an uniform fliape. 



Many of thefe were fquare at one extremit}^ making two right 

 angles ; and at the other end two oblique fides, making an acute 

 angle, as reprefented at fig. l6, T: others of them were oblique 

 at one end, and the other fliaped like the preceding figure, as is 

 fhewn at J?o-. 1 7, Y. Some few of thefe faline particles had the two 

 ends oblique, as f(g. 18, W, and a few others two fides oblique, 

 but one fide rather longer than the other, as/g-. ig, X. The longefi 



