'3 1 ° dn Attempt to make a Thermometer 
1 lie dry clay is to be foftened, for ufe, with about two fifths 
of its weight of water ; and formed into fmall pieces, in little 
moulds of metal, fix-tenths of an inch in breadth, with the 
hdes pretty exa&ly parallel, this being the dimenfion intended 
to be meafured, about four-tenths of an inch deep, aild one 
inch long. To make the clay deliver eafily, it will be neceftary 
to oil the mould, and make it warm. 
Thefe pieces, when perfe&ly dry, are put into another iron 
mould or gage, con fitting only of a bottom, with two fides, 
five-tenths of an inch deep ; to the dimenfions of which fides 
the breadth of the pieces is to be pared down. 
For meafuring the diminution which they are to fufter from 
the a&ion of fire, another gage is made, of two pieces of brafs, 
twenty-four inches long, with the fides exa&ly ttraight, divided 
into inches and tenths, fixed five tenths of an inch afunder at 
one end, and three-tenths at the other, upon a brafs plate ; fo 
that one of the thermometric pieces, when pared down in the 
iron gage, will juft fit to the wider end. Let us fuppofe this 
piece to have diminifhed in the fire one-fifth of its bulk, it will 
then pafs on to half the length of the gage ; if diminifhed 
two-fifths, it will go on to the narroweft end ; and in any 
intermediate degree of contraTion, if the piece be flid along 
till it refts againft the converging fides, the degree at which it 
flops will be the meafure of its contraction, and confequently 
of the degree of heat it has undergone. 
I hefe aie the outlines of what appears to me necefiary for 
the making and ufing of this thermometer ; and it is hoped, 
that the whole procels will be found fufficiently fimple, and 
eafy of execution. It may, neverthelefs, be proper to take 
notice of a few minuter circumftances, and to mention 
fomc 
