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vapour should be noticed, viz. the heat evolved in respira- 
tion. Beneficent nature always provides for her own wants 
in excess. The carbonic acid formed in the lungs gives out 
the needful heat to keep up the temperature of the warm- 
blooded animals, and the excess of heat so evolved is taken 
up by the water converted into steam and which is carried 
away in breathing. Now, if the whole of the heat so ab- 
sorbed in the steam were to remain as sensible heat in it, 
the 940° held latent therein would at once produce a tem- 
perature quite destructive of the living textures and would 
of course extinguish life. Thus we see another of the 
sublime laws of Providence is made to rest on these muta- 
tations of the imponderable elements. Little need here be 
said concerning radiating heat as apart from that of light, 
yet one instance may be cited, viz., the experiment of sus- 
pending a thermometer from the top of a glass-receiver on 
the table of an air-pump, then by rapidly drawing out the 
air the temperature will fall to or near the freezing point, 
but the mercury will again slowly rise till it reaches the 
temperature of the room ; but as the thermometer (attached 
by a non-conductor of heat) is quite isolated in a vacuum, 
how can the heat reach and re-enter the bulb, except it be 
by radiating from the external warm air through the glass 
and the vacuum, and thus restoring the equal temperature 
inside and outside of the receiver. This process is of the 
same kind as that of heat radiating from a common fire-place 
to warm a room. 
In my “ Notes on Heat in Relation to Atmospherical 
phenomena,” read at the Society, February 9th, 1853, 
besides adducing reason for assuming that all electrical and 
magnetical phenomena are simple consequences of the muta- 
tions of one pervading element, I have therein shown how 
most of the great aerial and oceanic currents may be traced 
to the acting forces generated by the mutations of heat, 
when they are excited in conjunction with those of gravity. 
