~~ 
64 Defcription of a new Thermometer. 
fions. The large tube may be 40 inches long, and not in+ 
creafed in diameter; but the fmall tube ought to be enlarged 
in diameter, and not in length. The alcohol will thus be af- 
_ feéted by heat or cold in as fhort a time as that before de- 
- feribed. ', 
* Tt is unneceffary to explain the clock-work. It is fuffi- - 
cient to fay, that a hollow cylinder of any light fubftance, 
4 inches Jong and 5 inches diameter, is made to revolve 
upon a vertical axis once in 31 days or a month ; a piece of 
fmooth vellum or paper is put round this cylinder, pafted 
only at the joining, but fo as to make it adhere clofe to the 
cylinder : on this are drawn 31 equal perpendicular divifions, 
numbered at top, I, 2, 3, &c. each of which is fubdivided 
into fix parts, to anfwer to 4 hours. The length of this cy- 
linder is divided by lines furrounding it, or zones, in fuch 
number as to correfpond to the feale of Fahrenheit’s therm. 
viz. from o to 100°. Thefe divifions ought to be engraved 
on copper, and a number of impreffions thrown off on 
fmooth or vellum paper, in order that one may be ready to 
put on each month. 
MN, fig. 2. reprefents the cylinder covered with one of 
“thefe impreffions: PP is the feale fixed to the frame in 
‘which the cylinder turns. The divifions on this feale cor- 
refpond,to thofe on the cylinder. 
Q is a piece of black lead pencil, joined to the end of the 
float-wire, in place of the knee before mentioned. This 
pencil is made to prefs lightly on the cylinder, by means of 
the {mall weight R. And as the pencil rifes or falls by heat 
and cold, it marks the degrees on the fcale of the cylinder ; 
and the cylinder being conftantly revolving, the divifion for 
each day and parts of a day will fucceflively be marked by 
the pencil, which will leave a trace, defcribing an undulated 
line, diftinétly delineating the temperature of each day 
through the month. Thefe papers, when taken off and 
bound together, will make a complete regifter of the tem- 
perature for the year; or, if they are patted to one another, 
in 
