Atmometric and Hygrometric Experiments. 51 
the atmosphere, thus agitated and intermingled, will be res 
duced to a still nearer equality of condition, 
‘In the regulating of many processes of art, and in di- 
recting the purchase and selection of various articles of 
produce, the application of the hygrometer would render 
amaterial service. Most warehouses, for instance, require 
to be kept at a certain point of dryness, and which is higher 
or lower according to the purposes for which they are “dea 
signed, The printing of linen and cotton is carried on in 
very dry rooms, but the operations of spinning and weaving 
succeed best in air which rather inclines to dampness. The 
manutacturer is at present entirely guided by observing the 
effecis produced, and hence the goods are often shrivelled, 
or otherwise injured, before he can discover any ahietelicnn 
in the state of the medium. But were an hygrometer, even 
of the most ordinary construction, placed in the room, it 
would exnibit every successive change in the condition of 
the air, and iminediately suggest the proper correction. The 
Same means could be ‘employed most beneficially, in ate 
tempering the atmosphere of public hospitals. 
“That wool and corn have their weight considerably 
augmented .by the presence of moisture, is a fact well 
known. Without supposing that any trawdubent practices 
are used, this difference, owing merely to the variable state 
of the air in which the substances are kept, may yet in ex- 
treme cases amount to 10 or even 15 per cent Grain or 
_ paper preserved inva damp place, will be found to swell 
nearly after the same proportion, Bunt the real condition 
of such commodities might easily be detected, by placing 
the fygrometer within a small wired cage and heaping 
over this, for a few minutes, a quantity of the wool or grain 
which is to be examined.” 
+ Ifa piece of cambric or linen be intensely dried, rolled 
around the bulb of a delicate thermometer, placed within a 
deep glass, and a stopped phial of water set beside it im 
a room, after one or two hours the whole will have ac- 
quired the same temperature. A little of the water in the 
phial is then to be poured ov the cambric; when the bulb 
of the thermometer will become instantly affected, and in- 
dicate the extrication of heat amounting to three. or four 
degrees of Fahrenheit. The heat evolved is always in pro- 
ortion to the previous dryness of the absor ing substance. 
With oak saw-dust, previously parched, the effect is still 
more striking. The tact of recently baked biscuits feeling 
hot in the mouth must be attributed to the same principle. 
“ The presence of heat likewise augments very considera- 
De bly 
