it been a hot iron, and it was cured in the same way. No surgeon in England, had he been called in, could hate suspected that it was not the effect of coming in contact with a hot iron. In truth, heat was the cause of the wound; and you will readily allow that I am correct, when I have explained to you a few circumstances.

Burning by a hot iron is produced by the heat, or what is technically called, caloric, passing in such quantity, and with such rapidity, into the part in contact with the iron, that the continuity and arrangement of the part is destroyed. Burning with a cold iron arises from the heat passing in such quantity, and with such rapidity, out of the part of the body in contact with the cold iron, as to produce the same effect. Heat in both cases is the cause; and its going into the body from the iron, or into the iron from the body, does not alter the nature of the effect.

It is the nature of heat to spread itself equally and uniformly through all bodies. Some receive it, and part with it more quickly than others do; their conducting

!

powers are different. When two bodies, of different temperatures, come in contact, the greater the difference is, the more violent will be the transmission of heat from the one to the other. Now, when you reflect that the temperature of the blood is 66 degrees above the freezing point (the freezing point is 32. of Fahrenheit, making 98. as the temperature of the blood), and that the temperature of the cold iron, which burnt me, was 28. below zero, that is, 60. below the freezing point, you have a difference of 126 degrees of heat. This difference is greater than what exists between the temperature of our blood (98.) and the temperature of boiling water, 212. which is only 114 degrees; so that it is not at all surprising that the transmission of heat should have been violent, and that burning should have been the consequence.

You will excuse me for leading you a little into these abstract matters. To assert that I was burnt with a cold iron, required something more to support it than the mere ipse dixit of the narrator, whatever his character for veracity might be. The thing, on a superficial view, is so contrary

Ú.

to our common-received opinions, that it was some time before I was quite reconciled to it. In theory, it was not new to me; and, as an opportunity occurred for proving the theory by practice, I was resolved not to neglect it*.

Analogous to being burnt with a cold iron, is the effect produced on the face when it is exposed to a very cold wind. The sensation is nearly the same as when it is exposed to a very hot wind, and the effect is precisely the same. When travelling in

* The idea of being burnt by a cold iron appears paradoxical, but it has been long familiar to chemists. Our great poet Milton, too, makes an allusion to the like effect of cold in his description of the residence of Satan and his compeers.-After describing Styx, he says,

"Beyond this flood a frozen continent

Lies dark and wild, beat with perpetual storms
Of whirlwind and dire hail, which on firm land
Thaws not, but gathers heap, and ruin seems
Of ancient pile; or else deep snow and ice,
A gulf profound as that Serbonian bog
Betwixt Damiata, and Mount Cassius old,

Where armies whole have sunk: the parching air
Burns frore, and cold performs th' effect of fire."

Paradise Lost, Book II.

Frore is an old word for frosty.-We have also in

Virgil, Georg. I. 1. 93.

Borex penetrabili frigus adurat.

a hot climate, and exposed to the operation of a warm wind, I have found that my face became red and inflamed, and, as it were, scorched. If rubbed with any kind of strong spirit, it smarted exceedingly, and perhaps the skin partially came off. The same sensations, and the same effects, are produced by a very cold wind, The principle on which they act, the cause from which they proceed, is the same-the too violent passage of heat into, or out of, the part affected.

There is another effect very frequently produced by cold in this country, which bears no analogy (as in the preceding example) to any thing produced by external heat; and a dreadful effect it is-I mean frost bitten.

When the weather is very cold, particularly when accompanied by a smart wind, instances of people being frost bitten, frequently occur. Not a season passes, without some of the sentinels being frost bitten on their posts. Sometimes, their hands and face, sometimes, their feet, are affected; and a mortification of the part generally follows, if the proper remedy is not applied

⚫ in time. The remedy will seldom be applied, if you are attacked in the dark, which is often the case with those who travel at night, as well as with sentinels. Their own feelings do not inform them of the presence of the enemy; and they are not likely, in the dark, to have him discovered by other people. He insidiously makes a breach; and if he can keep his ground but for a short time, it is in vain afterwards to think of dislodging him. In the towns, during the day, there is less danger, because you will be stopped by the first by the first person who observes the symptoms. This is readily and easily done, as the part frost bitten becomes white, while the rest of the face is very red.

In so critical a moment, people do not stand on any ceremony, as you may suppose. They know you are not conscious of your situation; and they also know, that before they could convince you that you are frost bitten, and on the point of losing your nose perhaps, it might actually be too late to apply the remedy; they instantly take a handful of snow, and either rub the part themselves, or make you do it.