attached by wiring or spindle to circular or triangular cement blocks, are dropped or lowered (depending upon the depth) to rest on the ocean bottom, where they remain for a year or two, until they reach a size proper for commercial purposes. They are then taken by the hook, 
A sheepswool sponge.
This is thirty-one months old, and was grown on a wire as in the illustration at the bottom of the preceding page. when new cuttings are attached, and the cement blocks let down again.
Another method was to string them on a wire held horizontal by stakes driven in the bottom. In doing this, however, various difficulties arose. The sponges became loose and rotated on the wire, enlarging the hole made through them, and the action of the salt water corroded and destroyed the wires, until, after many trials and experiments, a lead wire with a copper core was successfully used.
When the sponge cuttings are thus suspended freely in the water, growth takes place about equally in all directions; but when attached to one of the cement triangles or disks, the growth is most rapid in the horizontal plane. Experiments at Key West show that the cuttings two and one half inches in diameter increase in bulk from four to six times in six months.
The “seed” sponges must be transported to the culture grounds with considerable care, by packing them in tubs of wet seaweed kept at a temperature of seventy or eighty degrees. Some have been successfully packed in wet eel-grass and gulfweed. They must be kept moist and cool, and away from the sun’s rays and from fresh water, or they will not live. Even when growing on the culture farms, a heavy rainfall may so weaken the saltness of the water as to cause a high death-rate among the sponges affected by it. Shifting sands, entangling weeds, and storms are other happenings which make havoc with the sponge crop.
A sheepswool sponge, thirty-one months old, which was grown on a wire, is shown in one of the illustrations. This variety is unequaled for bathing purposes, and for use in the various arts. The larger forms are even used for gun-swabs in the army and the navy. They grow to be eighteen inches or more in diameter, are soft, of good shape, and readily absorb water. The color of the living sponge is black, becoming brownish at the base. The plan of the sponge culturist is to grow sponges in quantities large enough to be of commercial value, and that this may be done economically, they must be grown in water shallow enough to leave them easily accessible, without the aid of diving apparatus, which is expensive to maintain. Harry B. Bradford.
How the trade-winds help to make our sugar
A windmill used in grinding sugar-cane. built many big windmills, closely resembling those used in Holland. Barbados is near the
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