Vil. A PROPOSAL 
FOR ADJUSTING A NEW SCALE TO THE MERCURIAL 
THERMOMETER ; 
Inclosed wn a letter, addressed to the late Rev. President Willard, 
dated August, 1789. 
By EDWARD A. HOLYOKE, ». p. A. A. S. 
mem | EP | 
IT is matter of much regret, that an instrument so useful, 
so subservient to the purposes of philosophy, medicine, economy, 
and the arts, and which is so. frequently employed, as the Thermom- 
eter, should not hitherto have been furnished with a more natu- 
ral, useful, and commodious Scale; as there is not any one in com- 
_™mon use, that has fallen under my observation, that is not liable to 
great objections, or which has been formed upon such natural and 
philosophical principles, as might be wished, or as indeed might have 
been expected, considering the many able hands it continually p 
es through. These considerations led me to the following reflections, 
and must apologize for their communication. 
Fluids are the most convenient substances for forming Thermom- 
eters ; all solids being found very inconvenient and unmanageable for 
“common use. Now all Auids, fit for the purpose of a Thermometer, 
are liable, by great degrees of cold, to be congealed, and so converted 
into solids ; and can never therefore be a proper measure of any de- 
gree of cold greater, than what will just reduce them to a solid state. 
On the other hand, all such fluids are liable, by a certain degree of 
heat, to be made to boil ; after or beyond which point they dilate in 
an irregular and desultory manner, and cannot by any increase of heat 
be made to expand much farther; but, instead of expanding, are 
