508 PHILOSOPHICAL TRANSACTIONS. [anNO iGSl. 



were produced out of the eggs, and how they grew and spun themselves a co- 

 vering like the silkworm, and after several changes, turned into flies of several 

 kinds ; so I have now much laboured to trace the original of life in the male 

 seed of insects. And to my great satisfaction I have certainly discovered a great 

 quantity of animals, having the figure of serpents, but longer and thinner in 

 proportion, and shut up in small bladders about the size of a small sand, which 



1 take to be the testicles of those flies. And I am satisfied that flies have 2 of 

 those bladders, though I could find but 1 in some, because I suppose the other 

 might be broken by dissecting. But I am most surprised, that in the seed of so 

 very small a creature as a fly, there should be found living creatures so large in 

 proportion. 



I have found such animalcules in creatures of all sizes and species, from a 

 horse to a small horse-fly, and might have seen them possibly in smaller, if 

 their exceeding small ness and transparency did not hinder. I have often found 

 a great company of animals in the male seed of gnats, but smaller than those 

 of flies, and have often seen great quantities of eggs in the female, which 

 make her look larger and clearer. 



I have lately examined water, in which beaten pepper was steeped, and found 



2 sorts of animals for shape, and each of those sorts to contain greater and 

 smaller kinds; the greater I supposed the elder, the less the younger; I con- 

 ceive I saw in some of the greater sorts the young ones in their bodies; and 

 when I observed 2 swimming joined together, I conceived they were coupled. 



^ JVay of helping Short-sightedness. By Mr. Rob. Hooke. Philos. Collect. 



W 3, p. 59. 



Having found by many trials, that some short-sighted persons could find little 

 or no relief by the use of concave glasses, for seeing objects distinct at any dis- 

 tance; I considered whether convex glasses might not be made useful for that 

 purpose. Hereupon I considered the cause of short-sightedness, and finding 

 that any one might be made short-sighted, and to be able to distinguish nothing 

 but what is placed very near his eye, but within certain limits of distance, by 

 looking through a very deep pair of spectacles, such as old men use; I con- 

 cluded that what glasses should make this man, whilst looking through these 

 spectacles, see things at a greater distance, would also help any other person 

 that should be short-sighted by nature. 



Next I considered, that by the help of a convex glass, placed between the 

 object and the eye, the image of the object may be made to appear at any dis- 

 tance from the eye; and consequently all objects may thereby be made to ap- 



