R

OOMS are warmed to a comfortable temperature by conveying to them an amount of heat sufficient to make up for the loss resulting from radiation through walls and windows, the leaking of air around doors, windows, etc. The two most successful mediums are steam and hot water, for these readily absorb heat and as readily give it up to the surrounding air and objects.

Direct and Indirect Systems Both mediums are applied in systems, known as "direct" and "indirect." In the former, the pipes or radiators through which steam or hot water flows are placed in the room to be heated, and the heat is supplied from them by direct radiation. In the indirect, the coil or radiator is loIcated in the basement, or at the base of the flues leading into the room, and the air passing over it takes up heat and carries it to the room. In some respects the indirect system resembles furnace heating, for the hot air comes into the room through registers, no heating apparatus being in sight.

It is evident that the indirect system is preferable to the direct as to ventilation, for no ventilation occurs with the latter installation. With the indirect, considerable air is introduced in order to supply the required amount of heat. The efficiency of the direct system is, however, greater, for all the heat is supplied directly to the air and objects in the room, and there is less loss in transmit(342)

In large buildings it is often necessary to supply air in large quantities for ventilation. This is especially true of buildings of a public character, such as churches, schoolhouses, theaters, etc., for in these structures many people are contained in comparatively small space. In such cases, the natural circulation of air in the indirect system will not supply a sufficient quantity, and the direct system is useless for ventilation. To get the required air, it must be circulated mechanically, and this is best accomplished with some form of fan or blower.

The Blower

This machine is simply a sheet-metal casing of scroll shape, within which a steel-plate fan wheel revolves at high speed, taking air at the center or shaft, and giving it rapid motion by means of the revolving blades or vanes. Delivered at the tips of the blades, the air leaves the fan, under slight pressure, by a tangential outlet. For heating work, the fan is usually operated by a small steam engine, the set being called a "steam fan."

There are two distinct methods of fan

heating. In one, the air is heated in the basement to a high temperature (higher than that of the room). On entering the room, the heated air supplies enough heat to replace that lost through walls and windows. By the other method, direct radiation (steam pipes or radiators in the room) furnishes the required amount of heat, and a fan forces in air at the room temperature, to provide ventilation.

The first-mentioned method is better for buildings that must be kept warm all the time; it has the advantage of requiring the installation of but one system. The second is often selected for buildings to be ventilated but a few hours at a time; for the fan need not operate except when the occupants are in the building, and it is not necessary to supply more air than that required for ventilation. But two separate systems must be put in.

Plenum and Exhaust Systems The fan system may properly be divided into two classes, in the first of which the rooms are under a slight pressure; that is, the pressure within is just enough to cause all leakage to be outward. This is called the "Plenum." In the second, called the "Exhaust" system,

the pressure within the building is less than that outside, and air leaks in from all sides. Evidently purer air will be maintained in the Plenum, for it can be drawn from a reliable source.

The sketch on the blackboard shows the general arrangement of the apparatus used in the Plenum system. Air from out of doors enters through an opening into the Plenum chamber, in which a small heater, called the "tempering coil," heats it to about 70° F. It is then drawn into the fan, which forces it among and between the pipes of the main heater. As it is under slight pressure when it leaves the coils, the air passes up through the ducts to the rooms above. The apparatus is provided with suitable dampers, by means of which hot air, a mixture of the tempered air and the heated air, or the tempered air alone, may be directed to the rooms.

For warm weather, the air from outside may be passed through the fan, and thence to the rooms, without passing through the heater, thus supplying frequent changes of air.

The blower system has the advantage of being independent of the direction of wind, positive in action, and economical as to cost of running the fan; for the exhaust steam from the engine may be used in the heater.

THE

HE illustration shows a motor driven by the power the waves bear in their shoreward sweep. A sloping beach is necessary for the operation of the machine. Given surf and a favorable position on the shore line, the inventor believes his device should do excellent service. It is designed as follows:

A platform is constructed, with four standards, one at each corner. These standards support as many sheaves, over which two cables are passed. The cables are for the purpose of drawing the motor into or out of the water as may be de

COURTESY OF SCIENTIFIC AMERICAN."

A SURF-ACTUATED MOTOR.

sired. This object is accomplished by the turning of a crank. A series of buckets. attached to cables comprise the motor proper. As the buckets pass into the waves, they of course fill; and as they are drawn up by the cables, they are overturned and thus emptied of their contents. The motion thus set up is transmitted by cable to the machinery of a framework On shore. This cable

passes over a series of pulleys, to one of which is attached a counterweight. The purpose of the counterweight is to take up slack when the motor is drawn in toward shore. One of the pulleys is fixed to a shaft; and this, in turn, is connected with additional apparatus, consisting of levers, drums, and other gear, all of which complete the chain and keep the motor in operation.

Wooden Clothes

IT will probably not be very long before we can go into one of the dry-goods stores and say to a clerk, "Let me see

in

what you have in the line of wooden suits." He may reply, "Hard or soft?" whereupon it will be our part to specify that we want a suit of "good" pine, "without any cheap sapwood." Vests of this kind are already worn by the carding-room foremen some of the woolen mills. The material resembles a stiff, thick cloth, and is apparently as durable as leather. It is not improbable that in the future cheap suits. costing about 50 cents and guaranteed to last for years, will be made of spruce or pine. Napkins, shirts, collars of the finest quality, have long been made from the fiber of hemp; and in using wood for heavier cloth, the process is equally simple. The wood is first ground into a soft pulp, and this pulp is pressed through holes in iron plates. It comes out in long ropes about 1⁄2 inch in di

ameter. These ropes, which are very easily broken at this stage, are dried, and then twisted tightly, until finally they become as small as threads. Part of the threads are used for the warp, and part for the filling, out of which a strong web of wooden cloth is woven.

Calla Lily Farm IN California the calla lily flourishes in

superabundant profusion, and attains a degree of perfection rarely ever seen elsewhere. It is cultivated on a very large scale, for the sale of these flowers is immense. During the entire year, the plant flourishes in the open air, and its cultivation has become a very profitable industry. Great crops are raised, and scores of carloads are shipped to the cities and larger towns of California, where a ready market is found. These favorite flowers are also shipped into Nevada and other adjoining States in immense quantities.

What is probably the largest calla lily farm in the world is located in California. There is one 50-acre field in Ventura county devoted exclusively to the cultivation of these flowers. They are planted in long, narrow rows, and are cultivated by means of plows and hoes just like corn or potatoes. The lilies attain a very large size, and are perhaps the most beautiful

specimens of their kind to be found in the world.

Sweeps and Sprinkles THE automobile street sweeper and

sprinkler is a French invention designed to perform at once two kinds of work ordinarily done' separately. The dust that always arises after a disturbance of the pavement debris, is instantly downed by the almost simultaneous shower of water that follows hard upon the course of the sweeper.

For its cleanliness and labor-saving qualities, the invention commends itself. tank, having a capacity of 600 gallons of An automobile is built with a box or water. A brush, driven by chain and

sprocket, is raised and lowered by a lever at the driver's side. This brush sweeps a strip six feet wide. The sprinkler has a maximum spread of 20 feet. With an empty tank, the machine may attain a speed of 151⁄2 miles an hour. The motor is of 12 horse-power, and is adjusted to three speeds, 5, 11, and 15%1⁄2 miles an hour. These speeds depend upon the circumstances under which the machine is working. If the street is wet from rain or other cause, the pavement is, of course, simply swept without recourse being had to the water tank.

A Smoking Machine THE

HE champion cigar-smoker has been found in the Department of Agriculture at Washington. At each smoking, four cigars are consumed, all at the same time. Were such a record to be credited to any member of the personnel of the departmental staff, probably few of the important results announced from time to time from this center of activity would be heard of.

This smoker, however, is only a testing machine used for determining the quality of tobacco intended for cigars, with a view to producing an unrivaled quality of the fragrant weed. It smokes the four cigars with more regularity than any man could possibly accomplish the feat. It takes ten seconds steady draw, gives a puff, and after one-half minute

repeats the operation. Each cigar is watched carefully during combustion; and every detail affecting the filler, wrapper, binder, ash, and aroma is noted. The plant from which each cigar is made is known, and the seed of the one making the best showing is selected for future planting.

The cigars are placed in "mouthpieces" at the ends of several glass tubes leading to a bottle, which, through another tube, is connected with a flask containing a siphon. The flask and siphon act as lungs-breathing water, however, instead of air. The siphon comes into action when the flask is filled, the water being gradually drawn off, to be replaced with air drawn through the cigars. A special device is provided to make the action intermittent. Four cigars of average size can be smoked in half an hour.

Machinery has supplanted man's activity in many ways; but not even this product of ingenuity need arouse any fear that machinery is going to invade the sphere of man's "dear delights."