in different Branches of Science. tf I 



feen alfo by various aftronomers in other places. It pafled 

 the earth fix times nearer than the fun, which was the caufe 

 of its apparent motion being very rapid. It was fmall, ap- 

 peared only like a faint white fpot, and had no tail. Zach, 

 at Gotha, makes the number of the comets now known to 

 be 90. 



One of the moft difficult labours of aftronomy is what re- 

 lates to the ftars. Their immenfe number indeed is fufficient 

 to deter any one from the tafk of numbering them ; for 

 thofe which we fee, and we are far from feeing them all, 

 may be eftimated at more than a hundred millions. Many 

 of thefe it is well known have peculiar motions, fome of 

 which are very confiderable. It is to them, however, that 

 we are obliged to refer all the motions of the fun, the pla- 

 nets, and the comets. It is of importance then to endeavour 

 to determine the motions of the ftars *, and this object has 

 at all times engaged the attention of aftronomers. Mafke- 

 lyne has determined with the utmoft precifion the pofition 

 of 34 ftars. Zach has accomplifhed the fame thing in re- 

 gard to 1200. Lalande, with his nephew and niece, have 

 undertaken a labour far greater, to determine the pofition 

 of more than 40,000 ftars, from the arctic pole to the tropic 

 of Capricorn. This fublime tafk is already very much ad- 

 vanced, as the pofitions of 42,700 are already known. 



Hydrostatics. — Venturi has made interefting experi- 

 ments on the lateral efflux of fluids. He ihews that the 

 efflux is more confiderable, when a pipe, rather a little long, 

 is adjufted to the aperture of the veflel, than when there is 

 no pipe, or only one that is fhort. Thus, when one wifhes 

 to draw wine, the jet will be more confiderable by putting 

 a cock into the aperture of the caflc, than if there were 

 no cock ; and if the cock be fome inches in length, the 

 quantity that flows out will be greater than if it were very 

 fhort, 



It is well known, that when fmall bits of camphor and 

 other fub fiances, fuch as the juice of the euphorbium, are 

 placed upon water, they appear agitated in a very remark- 

 able 



