"Rapp's Gold Pens."--We cannot enumerate each person that we have sent Rapp's gold pens to. It would fill a column. We say, generally, every order has been filled; and gold will become scarce, notwithstanding the California supply, if orders multiply as they have done for the last month. See terms, page 276. EXPLANATION OF CROCHET TERMS.--Sc, single crochet; dc, double crochet; pc, plain crochet; pdc, plain double crochet; dsc, double stitch crochet; oc, open crochet; doc, double open crochet; tc, treble crochet; stc, single treble crochet; rc, ribbed crochet; ch, chain stitch; l, loup, and sometimes long stitch; sq, squares (in a tidy). The stars in work patterns denote repetition, and whatever is inclosed between two stars is to be repeated. Crosses and dashes often indicate the same thing. There are also sometimes used crosses, and sometimes stars within crosses, to avoid a deal of repetition, as the following: =X= 2 dc, 4 ch, miss 4, * 5 dc, 1 ch, miss 1, * three times, 5 dc, =X= twice. This would be at length, 2 dc, 4 ch, miss 4, 5 dc, 1 ch, miss 1, 5 dc, 1 ch, miss 1, 5 dc, 1 ch, miss 1, 5 dc, 2 sc, 4 ch, miss 4, 5 dc, 1 ch, miss 1, 5 dc, 1 ch, miss 1, 5 dc, 1 ch, miss 1, 5 dc. This mode, therefore, of stars, crosses, &c., very much abbreviates. No orders attended to unless the cash accompanies it. All persons requiring answers by mail must send a post-office stamp. Chemistry for Youth. HEAT, LIGHT, AND FLAME. A LANTERN TO GIVE LIGHT UNDER WATER.--The lantern must be made of leather, which will resist the waves better than any other substance, and must be furnished with two tubes, having a communication with the air above. One of these tubes is to admit fresh air for maintaining the combustion of the candle, and the other to serve as a chimney, by affording a passage to the smoke; both must rise above the surface of the water. The tube which serves to admit fresh air must communicate with the lantern at the bottom, and that which serves as a chimney must be connected with it at the top. Any number of holes may be made in the leather of which the lantern is constructed, into which glasses are fitted; by these means the light will be diffused on all sides. In the last place, the lantern must be suspended from a piece of cork, that it may rise and fall with the waves. * * * * * EXPERIMENT WITH A PIPE.--Compose a powder with one ounce of saltpetre, one ounce of cream of tartar, and one ounce of sulphur, pulverized singly, then mixed. Put a single grain of this powder into a tobacco-pipe, and when it takes fire it will produce a very loud report without breaking the pipe. * * * * *