C 6$6 ) 
Ihewn how to make this Inftrument without a Standard, 
or to make two of them to agree artificially without 
comparing them together. 
I thought to have finilhed this Difcourfe with (hewing 
a Method of conftru&ing and regulating Thermometers 
to the bed Advantage- but finding it neceflary to make 
fome Experiments with more Cunofity than I have yet 
done, efpecially upon the Airs Expanfions. I crave leave, 
till one of the next Tranfa&ions, to inform my felf 
more fully in thematter, being unwilling to leave to the 
Trial of others, what perhaps I have better opportuni- 
ty to examine my felf, efpecially in what is moft diffi- 
cult in this nice Affair ; I {hall only propofe, that where- 
as the uhal Thermometers with Spirit of Wine, dofome 
of them begin their degrees from a Point, which is that 
whereat the Spirit ftands when it is fo cold as to freeze 
Oyl of Annifeeds ; and others from the Point of begin- 
ning to freeze Water : I conceive thefe Points are not fo 
juftly determinable, but with a confiderable latitude: 
And that the juft beginning of the Scales of Heat and 
Cold ftiould not be from fuch a Point as freezes any 
thing, but rather from Temperature, fuch as is in peaces 
deep under ground ; where the Heat of the Summer, or 
Cold in Winter have (by the certain Experiment of the 
curious Mr. Marzotte in the Grottoes under the Obferva- 
tory at Paris) been found to have no manner of effe<Sk 
But of this more hereafter. 
An 
