VOL. XXVII.J PHILOSOPHICAL TRANSACTIONS. 663 



I observed also two other mites, which I judged to be females, before two 

 microscopes: one of these mites had laid two eggs, and the other three, and 

 as far as I could judge they were about three days old. I carried those micro- 

 scopes, together with the mites, in the day-time about me, and after ten days, 

 I observed that two of the eggs, which lay close by each other, had been 

 hatched, and that the young mites were come out of them, and the shells lay 

 open ; but I could not find the mites. As for the other three eggs, there came 

 a young mite out of one of them, on the same day; and on the 13th day came 

 out another mite, which could not thrust out its body above half way, and did 

 not live above a day. As for the third egg, it lay lengthwise to the sight, and 

 I expected before three days, that the young one should have come out, com- 

 puting that the animalculum was arrived to the full growth in the egg, and 

 that it had filled it in length and breadth, and there was also a transparency in the 

 egg; at last there came a little mite out of the third egg, but dead. 



On the 10th of November, 17O8, by means of glutinous matter, I stuck 

 two mites, which I judged to be females, on the point of a small pin; and on 

 the r2th of the same month, I found they had laid three eggs between them; 

 the next day there were four, and soon after six. I did not keep these eggs 

 warm, but let them stand upon my desk, to see how long they would be in 

 hatching, in that cold weather. December 8, I could perceive that one of these 

 mites stirred three of her legs, but after that time I could perceive no more life 

 in her. 



I viewed the said six eggs several times, and observed, that at the thickest 

 end of them (for they seemed to be exactly shaped like hen's eggs) they seemed 

 darker and darker; and on the 22d of December I could perceive on the thickest 

 end of one of the eggs, which stuck fast, a little mite, that had worked itself 

 so far out of the shell, as to make a continual stirring with four of its legs. 



The 25th of the same month, I further observed another mite got out of 

 its shell. From whence we may conclude, that as of hens and other creatures, 

 their chickens are not increased nor nourished in the eggs, unless the mother 

 sits on them ; and that all (heir eggs are hatched about the same time ; so here 

 on the contrary, the eggs of mites not being sat upon, but from time to time, 

 and the eggs laid on several days, the young ones must consequently be hatched 

 at different times. 



From these experiments we may observe what an influence warmth has on 

 the eggs of mites; for from those that I carried in my pocket, young ones were 

 produced on the eleventh or twelfth day, but those which I kept in a box on my 

 desk were not hatched in less than seven weeks. 



Thus we see how regular the production of a mite is, which was formerly 



