Rose G.—Gold has been mined from time immemorial, as the most ancient peoples used it for ornaments and for money. Before the introduction of coinage, gold for purposes of trade was probably in the form of lumps of different weights. Gold is mentioned in the Bible as early as the second chapter of Genesis, where, in the eleventh and twelfth verses, Havilah is spoken of as a land "where there is gold. And the gold of that land is good."—The use of steam as a propelling agent was recognized some time before a practical trial was made of its power. The first application of it as a motive force for vessels appears to have been made by Papin, a French mathematician and inventor, who, in 1707, made the experiment of propelling a small paddle-wheel vessel by steam on the Fulda River, at Cassel. The name of his vessel is unknown. Other experiments were made from time to time, but until Robert Fulton launched his little steamer on the Hudson River in 1807, nothing had been a success. Fulton's vessel, which was called Clermont, attained a speed of five miles an hour only, but from that time steam navigation progressed with rapid strides.—It is impossible to obtain an accurate census of large countries, but the following figures are taken from the latest estimates, and are probably not far from being correct: Chinese Empire, from 450,000,000 to 550,000,000; British Isles, 32,412,000; Mexico, about 10,000,000; Central America, 2,671,000; South America, 25,675,000.—There are many books giving epochs of United States history in story form. Some published within a short time by Messrs. Harper & Brothers are The Boys of '76, and Old Times in the Colonies, by Charles C. Coffin; Stories of the Old Dominion, by John Esten Cooke; and The Story of the United States Navy, by Benson J. Lossing.
Agnes B. W.—In Harper's Young People No. 32, June 8, 1880, is a paper entitled "A Chat About Philately," which gives a clear explanation of the terms which puzzle you.
C. J. K., Vermont.—We would gladly correct the error caused by the omission of a word in your letter, but we can not print any more offers to exchange birds' eggs. If you have any new exchange to offer, write it very clearly to the Post-office Box, and we will give space to it as soon as possible.
Correct answers to puzzles have been received from Hugh Burns, R. O. Chester, George F. Crego, Bessie Comstock, James L. Frazer, Louise Gambier, Albert H. Hopkins, Alice M. Hine, Isobel Jacob, Eddie Keeler, "L. U. Stral," Freddy E. Lester, Allie Maxwell, W. Olfenbüttel, "Starry Flag," Clara Spees, "The Dawley Boys," May Thornton, Walter J. Wells.