Philosophical Conversations (Paperback)

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: 25 CONVERSATION IV. COLD. (frederick, Robert, and Harriet warming their Hands at the Fire. The Morning very cold and frosty, and a heavy Fall of Snow. Mr. Powell enters the Boom.) Harriet. ? Papa, I am glad you are come at last; for now that the ground is covered with snow, and it is freezing so hard as almost to freeze us into icicles, do you still say it is not cold ? Mr. P. ? It feels intensely cold, my love; but our feelings, as Robert knows, may be mistaken; and I still say, and hope to prove to you, that there is no such thing as cold. Frederick. ? What is it, then, that makes the water freeze, and that makes us all feel so cold today? Mr. P. ? The short and correct answer to that question is, that the air is not so hot to-day as it was yesterday. Robert. ? But it was not hot yesterday, by any means; it was only not so cold as it is now. Mr. P. ? The air did not appear to us to contain any heat, because our bodies were so much hotter than the air, and, consequently, it deprived us of heat: but it certainly contained more sensible heat than the air does to-day; and I think I can make you aware that this frosty day is not without heat. Harriet. ? Do, dear papa, show us how, for I am now hivering with cold. Robert. ? With want of heat you should say, Harriet ? ha, ha, ha ! Mr. P. ? Yes, Robert, ridiculous as it may sound, that is correct. Even snow feels warm when compared with substances still colder, as I can convince you if you bring me a basin full of snow, and a cup full of salt. (robert brings in the snow and salt, as required.) Now put the thermometer into the snow, and see the temperature. Robert. ? It is 32. Mr. P.? That is just the freezing point; and it is, therefore, as cold as ice. I will now put part of the snow into an...