'Dr Page's engine, if used ten times during the day, of six minutes each time, would have but one hour's expenses for the day; whereas a steam-engine, under similar circumstances, would be subject to nearly or quite the full expenses of fuel for twenty-four hours, or equal to the expenses of continuous work.'
THE SCIENCE OF COLOUR IN DRESS.
Unfortunately for our health and comfort, the teachings of science are too often disregarded, if they interfere with our habits. Science, when not practically applied, loses its value; it wants fixedness, stability. Its application is its embodiment; without it, it is a mere figment of the brain. Its business is to inform the mind, and remove erroneous impressions; and its highest aim is usefulness. The popular belief with respect to dress, that a black dress is warmer, both in winter and summer, than a white one, is erroneous. The truth is that, the material being the same, a black dress is cool in winter and warm in summer—while a white one is warm in winter and cool in summer; that is to say, the one is cool when we require warmth, and warm when we require to be cooled; while the other is warm when we are cool, and cool when we are warm, and thus answers the purpose of dress, which is, to protect the body from the influence of the weather.
Science teaches that dark colours absorb heat, and part with it much more rapidly than light ones; black and white being the two extremes. How strange that this knowledge has not been applied to dress! If the bowls of two spoons, the one polished, and the other smeared with soot, be held near a fire, it will be found that the blackened one becomes hot much sooner than the other; and if now they be both made hot by holding them against the bars of the grate, and then removed from the fire, and suspended in the air, it will be seen that the blackened one will get cool much sooner than the other. It is true that the difference in this case is chiefly due to the polish on one of the spoons, but it is not altogether due to it. Again: if hot water be poured into two vessels, the one white and the other black, the water in the latter will cool before the other. So likewise if two persons, one dressed in black and the other in white—all other conditions being the same—were to go from the cold external air into a heated room, the one in black would feel the heat sooner than the other, and on leaving the room would feel the cold sooner; consequently, would be more likely to take cold than the other. It is therefore evident that a light-coloured dress is more conducive to health and comfort than a dark one, since it prevents the external heat or cold from too suddenly reaching the body, and prevents the body from too suddenly parting with its heat; and thus, that it keeps it in a more equable temperature.
We may now understand the reason why animals in the polar regions are white—their whiteness preserves the heat of their bodies much better than any other colour. So likewise the earth, in consequence of the whiteness of snow, is prevented from parting with its heat. It is not so much by snow protecting the earth from the external cold, that it does such valuable service, as by its preventing the radiation of the internal heat. This whiteness of snow, and of the polar animals, must not be looked upon as the result of blind chance: it strikingly exemplifies the wisdom and goodness of the Creator.
The above observations are peculiarly applicable to the case of men engaging in arctic expeditions. I do not know what dress they usually wear, but it is quite clear that a white woollen one would be the most appropriate; and if it had a gloss upon it, it would be so much the better. This they might have learned from observing the animals in those regions.
DIBDIN'S SAILOR-SONGS.
In a recent article in this Journal,[4] we gave our opinion of practical sea-life, and incidentally alluded to the songs of Dibdin. The paper excited some interest; and we may, therefore, venture to say a little more about these celebrated songs, concerning which the public in general has always had, and still has, a very erroneous impression.