semi-sailers, are not as good flyers in high winds, unless they spread their wings like a fan as the stork in figure nine, in order to give a little independence to the extremities of the feathers. But this slight defect is not sufficient to destroy the brilliant qualities of flight which these birds present; powerful rowers, they are masters of the air, not being, like the large sailing birds, at the mercy of a dead calm, which is always possible and many render them powerless. In short, the latter have taken their qualities from the two extreme groups; the rowers and the sailers in order to

utilize them according to circumstances. It is then the semi-sailers much more than the sailers that practice the most perfect flight, and man's imitation, which is often a criterion, gives actual proof of this. The aeroplane as it is conceived today, is only a semi-sailer with its screw propeller which allows it to take flight and sustain itself in the air, with its supporting and shifting planes, and its rudder which directs it. der which directs it. This gives us a hope that the day is not distant when automatic action will enable the machine to practice the true sailing flight without the aid of any motor whatever.

-T. W. PARSONS.

T

HE bumblebee is to be rendered almost superfluous in nature by a machine newly patented by an Indiana inventor-James M. Dennis, of Cambridge City.

This, at all events, so far as concerns clover and alfalfa plants, which have depended almost wholly upon the bumblebee for their production of seed. Where there are no bumblebees there is neither clover nor alfalfa. Which is why our government, not long ago, sent several batches of these useful insects to Australia, a bumblebeeless and cloverless country.

Up to date, it does not appear that the experiment has "panned out" as well as

was expected. But this is a matter of no importance if the "fecundating machine," as the inventor calls it, works as well as he claims it does. One such machine, he asserts, is equal for fertilizing purposes to a whole swarm of bumblebees.

The contrivance is a two-wheeled skeleton cart, and is intended to be driven by a man over a clover field. In the rear of the axle is a horizontal frame extending almost the entire width of the vehicle. This frame is interlaced with numerous wires in such fashion as to divide it up into an arrangement of square meshes.

It will be understood, then, that the interlacing wires join each other at right

SIDE VIEW, SHOWING THE "FINGERS" OF MACHINE FOR FECUNDATION OF PLANTS.

VIEW FROM ABOVE OF MACHINE FOR POLLENIZING PLANTS.

angles. From every joining there hangs downward a pair of spring-shaped wire fingers wrapped with some fuzzy stuff, such as lint or fibrous down. The fuzzy fingers thus prepared are made waterproof by dipping them in a thin solution of rubber. This is highly important, because they are the business members, so to speak, of the machine.

As the latter is driven slowly over the clover or alfalfa field, the horizontal frame, by an arrangement of cams, is made to move a few inches up and down. Four times during each revolution of the

cart wheels, they are lifted gently and dropped suddenly. This keeps the frame continually agitated; likewise the fuzzy fingers, which brush the blossoms, take up their pollen, and deposit it upon other blossoms.

In order that clover or alfalfa shall produce good seed, it is necessary that the blossoms shall be cross-pollinated. In other words, the pollen of one blossom must fertilize another. This is a task satisfactorily accomplished by the bumblebee; but Mr. Dennis claims that his machine does it equally well, and that it can be relied upon to fertilize practically all the blossoms in any patch.

A smaller machine is also being made now for similar use among strawberry plants.

T

HE chief purpose of a school building is to render children comfortable and to protect their health while they are being taught. This protection to health should be brought about with the minimum of attention from the teacher who is likely to be absorbed in the process of instruction.

In the building of the Elm Street School at River Forest, Illinois, the board of education has adopted an entirely new method of lighting and with such success that it has already been taken up by surrounding towns.

While the problems of heating and ventilating schoolrooms have been fairly well solved, the science of lighting has as yet received little consideration, though it has been brought to our attention again and again that a greater percentage of school children are suffering from eye-strain than from any other trouble. Many eye diseases, headaches and nervous disorders are directly attributable to the use of the eyes under improper conditions.

When we consider that the eye, whose loss is more deplorable than that of any other sense organ, is subjected to con

stant and serious abuse-and this, too, among children who have no means of self-protection-we do not wonder that the percentage of spectacled people is increasing so alarmingly.

It is common experience that strong light, shining directly into the eyes soon produces exhaustion and sleepiness. Yet there is scarcely one schoolroom in all this broad land in which a large proportion of the children are not forced to endure this strain. On the other hand a soft, steady and well-diffused light from overhead enables one to continue visual effort for a great length of time without fatigue. The explanation is simple. The pupil of the eye soon adjusts itself to this steady, well-distributed light, and no readjustment is necessary as the head is turned from side to side. Consequently vision is perfect, the retina protected and nervous energy conserved. In like manner, when one is out of doors the field of vision is illuminated by a steady, perfectly-diffused light and the pupil of the eye adapts itself to this unchanging intensity once for all and no harm done.

That the adjustment of the pupil of the eye to changing intensities of light is not instantaneous, is well known. In rooms lighted by side windows there are marked differences of light-intensity since the walls, absorbing much, reflect a soft light, while the glare from the side windows is unabated. As the head turns from side to side and the eye is met by widely varying light intensities, the slow-adjusting pupil is hopelessly unable to protect the sensitive retina. Vision is therefore obscured and nervous energy needlessly and harmfully wasted.

One of our illustrations shows a modern schoolroom-one that has always been considered well-lighted. The camera shows that part of the children are suffering from too little light and the others from too much, that the room is very unevenly lighted and that nearly all are subjected to severe eye-strain because of the great volume of rays bursting upon the faces of the children. Nature's provision-deep eye-sockets, eye-brows and eye-lashes-prove totally inadequate protection against this overwhelming light in front.