FRANK W.—­1.  According to Caesar, the first coins of what is now called Great Britain were of tin, and he has been substantiated by the discovery of pieces made of that material.  The first copper coins made by the United States Mint were one cent and one-half cent pieces, of which there were four designs, designated the “chain cent,” the “wreath cent,” the “flowing-hair cent” and the “liberty cap cent.” 2.  The letter, or mark on a coin designating the mint at which it was struck, is called the “mint mark.”  The U.S. coins struck at the parent mint, at Philadelphia, bear no such mark; those displaying a small “S” immediately under the denomination are coined in San Francisco, while “C.C.” stands for Carson City, and “O” for New Orleans.

EX-CONFED.—­A glue well adapted for any work which requires particular strength is made by dissolving an ounce of the best isinglass, by the application of a moderate heat, in a pint of water.  After straining this solution an ounce of the best glue, previously soaked in water for twenty-four hours, and a gill of vinegar should be added.  After all of these materials have been brought into a solution, the mixture should be allowed to boil up once, and then the impurities must be strained off.  A handy method of making glue for ready use is to employ common whisky instead of water in dissolving any quantity of glue.  Put both together in a bottle, cork it tight and let it stand for three or four days, when it will be ready for use without the application of heat.

BIRDIE HAIGHT.—­1.  The American swan breeds in the northern parts of America, and its migrations extend only to North Carolina.  Another American species is the Trumpeter Swan, breeding chiefly within the Arctic Circle, but of which large flocks are seen in winter as far south as Texas.  It is smaller than the common swan, which is found in its wild state in Asia and the eastern parts of Europe.  In a half-domesticated state it has long been a common ornament in lakes and ponds in this country and Europe, more especially the latter.  The black swan is a native of Australia. 2.  Varicose veins, it is said, may be radically cured by a surgical operation, but the disease may reappear in some other portion of the body, there being no way to prevent it. 3.  Papua, or New Guinea, is the largest island in the world.  Australia now ranks as one of the grand divisions of the earth.

S.A.M.—­Eighteen articles on electricity have been published in this and previous volumes.  They were:  “A Cheap Electrical Machine,” Vol.  II, No. 22; “How to Make a Simple Electrical Machine,” Vol.  VI, No. 3; “Experiments of Various Kinds,” Vol.  VI, No. 4; “A Storm in a Teacup,” Vol.  VI, No. 9; “The Leyden Jar and How to Make It,” Vol.  VI, No. 20; “The Electrician at Home,” Vol.  VII, No. 16:  “A Mysterious Alarm,” Vol.  VIII, No. 14; “Studies in Static Electricity,” Vol.  IX.  No. 30, “How to Make an Electrical Machine,” Vol.  IX, No. 20; “How to