3830.] 
On the Scale of Temperature. 
23 
whence it is drawn by the blacks at low water, and is eaten in great quantities. 
Perhaps the large Melania of the Gumti might afford a delicate morsel to our Eas- 
tern “ gourmets Le Gentil, however, does not inform us how they are prepared. 
It is desirable that the animal of Pirena, which inhabits the marshes of Amboyna, 
and, perhaps, also of Southern India, and which Lamarck, from inspection of the 
shell, placed in the same family with Melania, should be compared with ihe descrip- 
tion of the latter, and their points of similarity or difference noted. 'W' H B. 
Bundelkhand , 
October 1829 . 
VI. 
Sir, 
-On the Scale of Temperature ; with Remarks on the Graduation 
of Leslies differential Thermometer. 
To the Editor of the Gleanings in Science. 
The writer of the remarks, in your number for September, ou the i node of tern- 
perature, has, in recommending the adoption of the universally con 
an scale, given a partial view of the subject. . . f 
Did all bodies, like water, suffer a diminution,— and the same d “" in ^ tl ®°’ ot c *~ 
parity for caloric, concurrent with the rise of their temperatures, the Daltonmnand 
common scale would he on an equality in point of truth ; the fin mier -i g 
actual , and the latter the potential or sensible quantity of heat : 
substances differ, not only in their capacities for caloric at one 
each in its own capacity at different points ot the thermometric range, no useful m 
formation could be derived from a scale adapted to the varying capacity of any 
substance, unless that substance were the very fluid constituting the tbtrmometCT , 
and in the case of a mercurial thermometer sucb a scale would not sensdd> differ 
from the common division into equal parts, .tbe modifications re^ J* rQ l 
ly varying capacities of mercury being so minute as to fall within the limits of erro 
m Mr!* Dalt^’s^proposal, however, differed widely from this. With the increase 
of their temperatures it is probable, that all bodies acquire as mall 
crease of capacity for caloric,— all except water, which with the increase of temper- 
ature suffers a great diminution of capacity for caloric ; and water, the striking ex- 
ception Mr. Dalton would make the general rule, dividing the scale according to the 
quantities of heat which it alone required for attaining a given temperature. He 
might with equal advantage have perplexed the 
tiig m?e ki -ep°ho:r geuVril » heat, an'd perhaps both equal.y 
which he 6 h^d ^ prev^ouriy ^orda^ne^ *for ^ the government" of the universe ; and the 
c m- nviv nerhaps be regarded as another portion of the same great design. A 
£e fixing of ’the maximum density of water at 
still further adapted, at moderate temperatures, for Lciw 
by the reversal of theosual law, and being 
— r tothe 
1>0 These reflections ought to make us wfefied ut^from indeaTOtiring to extend 
this particular, a solitary exception, ^periincnts planned and executed with a bias, 
its phenomena to other bodies, byexperimen P 
like those on mercury mentioned by your corre p ’ 
