^o D.y'cnpiion of a Spring in the Sl<t. 



rained : thefurrounding water is on the other hand perfectly 

 transparent. Thefe radii will not fuller a boat to remain 

 iieady on the centre of the button, but, as may be readily 

 fuppefed, throw it back to the circumference. M. Spallan- 

 zani, however, found means to fix himfelfin that pofition > 

 and was thence enabled to examine carefullv the water at the 

 bottom, as vf eld as that at thefurface. 



The water at the furface is not frefli, but a little lefs fait 

 than that by which it is furrounded. The depth of th.: 

 fpring is 38^ feet. When the heaving-lead approaches the 

 bottom, it is obferved that the fmall line to which it is 

 made fall begins to tremble ; and as this trembling is ob- 

 ferved no where elfe, it is plain that it is occafioned by the 

 violent impulfe of the water of the fpring againd the bottom 

 of the lead. The water being lefs fait at the furface than 

 the fea-watcr, with which it has mixed itfelf, it is natural to 

 fuppofe that it is perfectly frclh at the bottom. To afcer- 

 tain this, M. Spallanzani invented a machine, by which he 

 could draw up fomc of it from the bottom, in fuch a man- 

 ner as not to be mixed with the fait water by the way; and 

 the water pjocured in this manner, though exceedingly tur- 

 bid and ilimy, was found to be perfectly frefli. He re- 

 marked alio, that this water, when compared with the fea- 

 water, was remarkably cool, which arofe probably from its 

 riiinji' from fome depth under the earth. The brafs machine 

 alto was once very much beat together, which could be oc- 

 taiioned by nothing elfe than the violence with which the 

 water iffiied from the ground, and by which the machine 

 lw.d probably been dallied againft a ftone. 



M. Spallanzani is of opinion that the origin of this fpring 

 is as follows : — There are two fmall dreams which flow from 

 the fide of a hill at the diftance of three miles from Spezzia. 

 '1 hd'e dreams are afterwards united, and throw themfelves 

 into an unfathomable abyfs, from which the water, as it is 

 fulhciently fecured from the dimmer heat, forces its way 

 through the earth, and fupplits fufficient nouriflanent to the 

 \^a that fprings up through the fajt water,. 



