376 PHILOSOPHICAL TRANSACTIONS. [aNNO 1677. 



eye, I make the proportion of one of these small water- creatures to a cheese- 

 mite, to be like that of a bee to a horse ; for, the circumference of one of these 

 little animals in water is not so large as the thickness of a hair in a cheese-mite. 



In another quantity of rain-water exposed for some days to the air, I observed 

 some thousands of them in one drop of water, which were of the smallest sort 

 that I had seen hitherto. And in some time after I observed, besides the ani- 

 mals already noted, a sort of creatures that were eight times as large, of almost 

 a round figure; and as those very small animalcula swam gently among each 

 other, moving as gnats do in the air, so did these larger ones move far more 

 swiftly, tumbling round as it were, and then making a sudden downfal. 



In the water of the river of Maese I saw very small creatures of different 

 kinds and colours, and so small, that I could very hardly discern their figures ; 

 but the number of them was far less than of those found in rain-water. In the 

 water of a very cold well in the autumn, I discovered a great number of living 

 animals very small, that were exceedingly clear, and a little larger than the 

 smallest I ever saw. In sea water I observed at first, a little blackish animal, 

 looking as if it had been made up of two globules. This creature had a peculiar 

 motion, resembling the skipping of a flea on white paper, so that it might very 

 well be called a water-flea; but it was far less than the eye of that little animal, 

 which Dr. Swammerdam calls the water-flea. I also discovered little creatures 

 therein that were clear, of the same size with the former animal, but of an 

 oval figure, having a serpentine motion. I further noticed a third sort, which 

 were very slow in their motion; their body was of a mouse colour, clear to- 

 wards the oval point; and before the head and behind the body there stood out 

 a sharp little point angle-wise. This sort was a little larger. But there was yet 

 a fourth sort somewhat longer than oval. Yet of all these sorts there were but 

 a few of each. Some days after viewing this water, I saw 100 where before 

 I had seen but one; but these were of another figure, and not only less, but 

 they were also very clear, and of an oblong oval figure, only with this differ- 

 ence, that their heads ended sharper; and although they were a thousand times 

 smaller than a small grain of sand, yet when they lay out of the water in a dry 

 place, they burst in pieces, and spread into three or four very little globules, 

 and into some aqueous matter, without any other parts appearing in them. 



Having put about one-third of an ounce of whole pepper in water, and 

 it having lain about three weeks in the water, to which I had twice added some 

 snow-water, the other water being in great part exhaled ; I discerned in it with 

 great surprise an incredible number of little animals, of divers kinds, and 

 among the rest, some that were three or four times as long as broad; but their 

 whole thickness did not much exceed that of the hair of a louse. They had a 



