This is the last month of the special prize offers. Some of our readers will secure valuable tools, and the magazine a largely increased list of interested readers.

The near approach of Christmas leads to the suggestion that new subscribers are easily secured this month if a little thought is given to selecting those who would be likely to be interested in the magazine. But few subscriptions are necessary to secure some of the many excellent premiums offered.

The large holiday business at the bindery has delayed the delivery of the bound volumes much beyond the time when they were promised, but volume II is now ready, and the reprint of volume I is nearly complete, and will soon be ready for delivery. These are excellent for Christmas presents.

The special premium offer of a Weno 3 1/2 x 3 1/2 camera for five new subscribers is an opportunity of which early advantage should be taken, the supply being quite limited, and the offer cannot again be made. See our advertisement for particulars, and learn that this is a chance to secure a fine camera with but little trouble.

Rock-salt mining is carried on extensively in five districts of New York State. The shafts are sunk in the usual manner, and the sides are prevented from caving in by heavy timbers, while to prevent water from entering the shaft a heavy layer of cement is put between the walls of the shaft and the timber. The shafts vary in size somewhat, the usual dimensions being 12' x 18', and 24' square in the clear. The main galleries are about 30' wide, their height depending on the thickness of the salt beds. Some salt must always be left as a roof and floor; hence, in a vein of salt 24' thick, an allowance of 6' for the roof and 4' for the floor would give a gallery or chamber 14' high. From the main chambers cross sections or galleries are run every 30'; thus the roof above is supported by pillars 30' square. The salt is blasted out with dynamite. The drills are run by compressed air about 6' into the solid salt, and they are set in such a manner that when the blast takes place, as much as possible of the salt remains in lumps. The salt is loaded into small cars, which are run on tracks laid on the floors of the chambers on to cages in the shaft, through which they are carried or hoisted to the top of the breakers, similar to those used in coal mining, and from 100' to 145' above the surface of the ground. To separate the lump salt from the finer material, the contents of the cars are dumped on a set of iron bars, which permit all the salt, except the lumps, to fall through into the crusher below ; the lumps are loaded on to other cars and run down an incline to the ground, where they are stored, usually in the open air, for shipment. The finer material passes through the crushers on to sieves, and from the latter into the bins. Of the crushed and sifted salt, there are four kinds, according to size. The lump salt is mainly used for stock, the other grades for the same purposes for which sea or solar salt is required.

Sycamore, a most durable wood, is the sub-stance of a statue known to be nearly six thousand years old, and now in the museum of Gizeh, at Cairo. The wood is stated to be quite sound and natural in appearance.