i8 7 S.j 
to Health and Comfort. 
2ol 
breath and the exhaust steam from the workshops evolve a 
cloud of apparent vapour, which must condense in cooling 
as the air absorbs its heat, for the saturation of the air for- 
bids its absorption as an invisible gas. A Scotch mist of 
36° (which is only a supersaturated air with vapour in excess 
at a slightly higher temperature than the air) penetrates 
clothing, and reaches every part of the person with distress- 
ing frigidity. 
Passing upwards in the scale of temperatures from 50° to 
65°, the point of equilibrium of cooling aCtion by conduction 
or radiation of vapour in the air, with supply of heat from 
checked evaporation of the skin or lungs for attainment of 
comfort, seems to be reached. Perhaps the most healthful, 
or at least most stimulating, atmosphere for human breath- 
ing is found within these limits, when of natural and con- 
tinued existence, so that within and without the doors the 
same condition exists, and the regime of the bodily system 
is not disturbed from hour to hour. This, if not the ruling 
climatic condition of English life, at least is the presumed 
theoretic standard of English writers. Mental or physical 
exercise alike, either separately or in conjunction, are sup- 
ported by this condition of the atmosphere to an extent 
which no inhabitant of the frigid north or enervating south 
can imagine. 
Some curious physiological phenomena accompany this 
atmospheric condition, one of which is the possibility of use 
of stimulants of the milder nature (wine and malt liquors), 
in quantities which would be immoderate in our climate. 
With the comparative cessation of cutaneous evaporation, 
it seems as if aCfion of the alcoholic ingredient of the 
liquors were much changed and rendered more stimulating 
and less intoxicating. 
From 63° to 8o° a saturated atmosphere is sultry and 
oppressive. The surplusage of heat cannot be removed by 
conduction, and the natural effort of the system is to induce 
evaporation. The least physical effort produces, in the 
healthy person, abundant sensible perspiration, and the 
cooling effeCt of evaporation of a heated surface of water 
into a cooler air is the natural remedy. The lassitude and 
enervation of this step in the scale is eminently unfavourable 
to mental as well as to physical labour. 
Above 8o° a saturated air becomes burdensome ; it is even 
questionable if life could be prolonged in a saturated air of 
90° to ioo°, and it is certain that at some point, not much 
above ioo°, suffocation would ensue when any exertion 
should raise the animal heat above its normal degree. The 
