74 DIMINUTION OF DlLATADirjTV IN SPIRH' THERMOMETERS 



nUniudilata- Uses part of its dilutabiliiy. Noilet and Brissoii maintain 

 ^''"y* tile contrary, on tlie expejieiicf, hs tlu-y say, ot* more thau 



thirty years. The two.foliowiuj; tacts howevvr confirm the 

 opinions of Ha!1ey atitl ?»Inschenibroeck. 

 This sK->wrn in I have u spirit of wine tlurniometer, mude in 1734 by 

 K<^l"^^*^'^ ^^ Mr. Nollet, on tlie prin^riples and under the in»p€ctiou of 

 Reaumur. From fear, no doubt, that the wire marking 

 the freezing point minht be displaced, Mr. Nollet wrote 

 with his own linnd on a paper pasted on the inside of tbe- 

 lid of the cas<i of the theiinometer the followinir note: 

 ** The upper extremity of the stem of the thermometer 

 "ought to be at 94'':'* and at tlii* point he has ^nade a 

 groove. Hence it was easy for me to place it cxactlyvin 

 the same situation, as when it came out of the hands, of 

 that able philosopher. V/hen I was tljoronghly certain of 

 this, I pia'ed the thermometer in a vessel full of pounded 

 ice, jubt meltinor; and in this state I kept it t'.iree days, 

 fiddint^ fresh ice, when the former was half melted, and 

 draininor otr the water. The Tujaor in the thermometer set- 

 tled a degree and a quarter below nought, and remained 

 stationary at this point during the whole time it remained 

 in the ice. This experiment was made on the 7th of March, 

 1807, and the two following days, 

 aticf another by I have another spirit thermometer made before 1758, ac- 

 Jtomieu. cording to Reaumur's principles, by Mr. Romieu, a learned 



natural philosopher of the Royal Society of Sciences at 

 Montpellier, whose accuracy is generaMy known. This 

 thermometer is enclosed and fixed in a large glass tube her- 

 metically sealed, 60 that it cannot have been deranged. I 

 placed this at the same time in a vessel of melting pounded 

 ice, with "which it was cotnpletely surrounded ; and during 

 the three days that this experiment continued, the spirit of 

 wjue continued stationary at two degrees and a quarter below 

 nought. 

 Inter.rfecT to be 1 preserve these thermometers, though grown very defee- 



tried again at a ^j -^ order to try whether their dilatability will diminish 

 firture period. ^ * / . % 



still farther, in the mean time these observations appear 



lo me sufficient, to induce us to reject the use of spirit of 



Trine thermometers; and keep to those of mercury, which 



^o wot appear lijab^e to, ^be st^mc ii)coavenience. 



HEMARKS. 



