98 PHILOSOPHICAL TRANSACTIONS. [annO 1 696. 



But I observed that those irregular particles, which are inherent in the 

 globules of glass, were seen distinctly and prodigiously magnified, as was easy 

 to imagine, both from their nearness to the eye, and because they did not hinder 

 the globules, either by day or candle-light, from appearing throughout trans- 

 parent, being so minute as not to be discernible, except held close to the eye, 

 as in time of observation, and not then neither, if too near the light, but 

 at a competent distance, they appeared as above. I knew not well how at that 

 time to account for this strange phenomenon, that an object should be placed 

 so far within the focus of a spherule, as to be within the glass, and yet seen 

 distinctly to the eye so near it; but since by matter of fact, I found it was so, 

 I made this inference, and concluded, that if I conveyed a small globule of water 

 to my eye, and that there were any opacous or less transparent particles than the 

 water therein, I might see them distinctly. 



Having by me a small bottle of water, which I knew to have in it some of 

 those minute insects which Mr. Leuwenhoeck discovered, by the help of ex- 

 cellent microscopes : having seen them with the common glass microscopes, 

 and with the first aqueous, as abovementioned, I poured a few drops of this 

 water on the table, and taking a small portion of it on a pin, I laid it on the 

 end of a small piece of brass wire ; I continued to lay on two or three portions 

 of water, till there was formed somewhat more than a hemispherule of water ; 

 then keeping the wire erect, I applied it to my eye, and standing at a proper 

 distance from the light, I saw them and some other irregular particles, most 

 enormously magnified; for whereas they are scarcely discernible by the glass mi- 

 croscopes, or the first aqueous one, within the globule, they appeared not 

 much different both in their form, nor less in magnitude than ordinary peas. 

 They cannot well be seen bv day- light, except the room be darkened, after the 

 manner of the famous dioptrical experiment, but most distinctly by candle- 

 light ; they may be very well seen by the full moon light. The pin sometimes 

 takes up the water round enough to show its objects distinct. 



The insects I have as yet this way observed, are of two sorts, globular and 

 elliptical ; I shall first describe the former. They are of a globular form, and 

 are but a little less transparent than the water they swim in ; they have some- 

 times two dark spots diametrically opposite, but these are rarely seen ; there 

 are sometimes two of these globular insects sticking together; where they are 

 joined it is opaque ; they have a twofold motion, a swift progressive irregular 

 one ; and at the same time a rotation on their axes at right angles to the dia- 

 meter that has the dark spots ; but this is seen only when they move slowly. 

 They are almost of an incredible minuteness. Mr. Leuwenhoeck is moderate 

 enough in his computation, when he tells us (Philosophical Transactions, 



