300 Remarks on Self-Registering Thermometers. 



fostered and encouraged. Let public honours and national 

 rewards be bestowed on those who add to its perfection. Let 

 our men of science be induced, like Euler, JBou guer, and Chap- 

 man, to look to it as an object to which their high attainments 

 may be applied, with the full and certain prospect of honour 

 and renown. 



Plymouth, August 12, 1828. 



Art. XVII. — Remarks on Self-Registering Thermometers, 

 particularly on Mr King's* described in last Number. Com- 

 municated by the Author. 



Sir, 



One of the most important and interesting, but at the same 

 time unfortunately one of the most imperfect of our meteoro- 

 logical instruments, is the self-registering thermometer. Al- 

 though the ingenious principles on which it has been con- 

 structed are perfectly good in theory, yet from a certain de- 

 gree of mechanical complexity with which they are always ac- 

 companied, and the consequent pains required in constructing 

 them, they are seldom found equally unexceptionable in prac- 

 tice. It is not my intention at present to enter upon the ge- 

 neral and particular defects of register thermometers and their 

 remedies, which it would require an extensive series of expe- 

 riments with the instrument in various forms to be able to 

 write upon in a manner commensurate with the importance of 

 the subject, or worthy of a place in the pages of your Jour- 

 nal. My present intention is merely to make some remarks 

 which suggested themselves to me on the perusal of a paper 

 connected with this inquiry by Mr King in your last number. 

 The first form of the instrument which Mr King has de- 

 scribed (No. xvii. p. 114, &c.) is manifestly too complex to be 

 generally and accurately useful, and nothing could be less con- 

 formable to the principles of the art than the proposal of mak- 

 ing the legs separately, and then joining them. The same fun- 

 damental plan is adopted in the second form of the thermo- 

 meter described in page 116, to which I beg to refer the 

 reader ; and the mode of indication is every way simple and 



