Theory of the Magnetical Variation. 295 
themselves between those of any other body, is the cause of alk 
expansion—that they decompose some bodies, but never mix 
with any; and are repulsed by all, when containing a eplanity 
unnatural to them. 
Now, sir, my conception is (probably an erroneous one) that heat 
is onlya sensation arising from the sudden decomposition of a body, 
and that when it isdecomposed it cannot communicate the feeling. 
If a coal is burning or decomposing, it can give the disease to an 
adjoining coal; and this disease will pass like lightning between 
the particles of the bottom of an iron steam boiler, and commu- 
nicate the complaint to the water: the first disorganization of 
which is steam. Pursue the disorganization in the steam still 
further, until you get a pressure of 50 or 60 lbs. to the inch, and 
the steam will then be only milk-warm, from the decomposition 
being so nearly complete. If heat were an elementary principle, 
and its particles went through the iron and water without mix- 
ing, they would equally pass on through the top and sides of the 
boiler, more particularly upon the repulsive principle. ‘The ex- 
pansion of metals may arise from a partial decomposition, which 
if discontinued, their particles will fall again into their former or- 
ganization. I believe any sudden disorganization produces light— 
probably the decomposing and regenerating principle, acting ra- 
pidly upon the animal and vegetable organization on the sun’s 
surface, may cause its light, and disorganizes on the earth less 
(and therefore less sensation of heat) in winter than in summer, 
because the sun’s light then falls much more obliquely upon the 
earth, and meets with more atmospheric obstruction. Thesame 
principle acting upon the growing animal and vegetable system 
here, is very likely to stimulate by vacuum, and the stomach and 
capillary system to supply reorganization, and all generative prin— 
ciple. 
I wish to throw out these ideas (very hastily put together) to 
your better informed readers, if you think them worthy a corner 
of your valuable miscellany. Your obedient servant, 
Claughton House, Lancaster, S. 8S. 
17th October, 1818. 
— 
XLVIII. Theory of the Magnetical Variation. By Mr. 
THomas YEATES. 
Taz discovery of the properties of the loadstone having been 
the labour of ages to explore, and an object with the searchers 
of nature from the earliest times; it would be a curious and in- 
teresting inquiry to ascertain the several stages of the knowledge 
of this wonderful stone. To enter upon its history is a difficult 
task, from the want of many notices of which history itself is si- 
lent, and without which thé progression of the discovery must 
T4 necessarily 
