_Cerasin_ is the insoluble portion of the gum of the cherry tree, and is nearly like _bassorin_. Mr. Schmidt has determined the composition of these various substances, and has found them all more or less allied to starch, invariably containing hydrogen and oxygen, the proportions in which they form water, and all when treated with acids yield grape sugar. The jelly of fruits or _pectin_ is closely related to the gums, but as yet chemists have not paid much attention to it, and consequently much that is said of it is merely conjectural. GUM ARABIC CEMENTS. Gum arabic, dissolved in as small quantity of water as may be, and diluted to a proper consistence with gin, or any proof spirits, forms a very useful cement for all purposes where gum-water is commonly used, the spirit preserving it from becoming putrescent. As the spirit evaporates, more should be added. It should be stirred and mixed together at the time of using. If plaster of Paris be added to gum-water, it makes a cement useful to ladies in filigree works. Gum ammoniac added to the solution of gum-arabic in proof spirits very much improves the cement. It answers very well for joining broken glass and ornamental articles of porcelain. DIRECTORY. In order to enable strangers and merchants from abroad, as well as those residing in New England, to readily find some of the leading houses in Boston representing the various branches in the BOOT AND SHOE AND LEATHER TRADE, also some of its collateral helps, in the way of Important Inventions, Agencies, &c., we have inserted Advertisements and Cards of a few among the many that we know to occupy highly respectable and reliable positions. Our space is necessarily limited, and we therefore present but a brief list, yet sufficiently large to represent every important interest, also some of the most valuable Labor-saving Machines and Inventions, which are of _great practical utility to the manufacturer_. ------------------------------------------------------------------------ VULCANIZED RUBBER SOLES. This Soling has been growing in favor with the public for the past few years; and recommending itself as it does, for its ECONOMY, DURABILITY AND COMFORT, and as a great preserver of health, being perfectly WATER PROOF, deserves general introduction to the people. It is manufactured in sheets about thirty inches wide, and from one-sixteenth to three-sixteenths of an inch thick, suitable for the thinnest slipper or the heaviest boot. Its application is perfectly simple. Cement for putting it on, being furnished by the same manufacturers. PRICE: =SOLING= 65 cents per pound, =CEMENT=, in boxes, No. 1, $9.00; No. 2, $4.50; No. 3, $3.00 per doz. DISCOUNT from the above prices made to the trade.