Rensselaer Journal, Volume 11, Number 22, Rensselaer, Jasper County, 7 November 1901 — NOTES ON SCIENCE. [ARTICLE+ILLUSTRATION]

NOTES ON SCIENCE.

CURRENT NOTES OF DISCOVERY AND INVENTION. Danger to Health in* School Room* —A Wire Fence Convenience —Carved Bale Invented by a Russian —The Smallest Watch. ' DANGER TO HEALTH IN SCHOOLS. Many people who are scrupulously aareful of the health of their children in the home are strangely indifferent to the conditions prevailing in the school. Hygiene in the public schools Is a subject that is yearly receiving more and more attention, with the remit that new school buildings in the larger towns and the cities conform generally to sanitary standards, but this is not true of many of the old buildings and of many schoolhouses in small places. It is the duty of all parents to know how far they fall short, and why, and what is needed to make them healthy. The rules as to contagious diseases Bhould be more strict, or rather more Strictly enforced, and parents should remember that danger may lurk in complaints often considered of slight Importance. Whooping-cough, for instance, is thought by many people to be an unimportant and necessary trouble of childhood which it is better to get over and have out of the way. They do not kndw, or they forget, that while whooping-cough is not a dangerous disease for older children, it Is dangerous and often fatal to very young children, and is easily carried by the children attending school to the babies in the nursery. ■ Too much attention cannot be paid to the question of light in the schoolroom. Many children are made premature wrecks from unrecognized eyestrain, and school visitors may often see small, helpless children .sitting blinking in the sunlight which streams through a large window in front of them, making frowning efforts through the blare to read from a blackboard, and using up in a few hours the nerve force of a week. Light should be abundant and should come from the left side, so that no shadow is thrown on slate or book, as is the case when the light comes from behind or from the right. Another most important matter is the properly constructed desk, which will prevent undue stooping, contortions, or Impediment to correct breathing. In considering the subject of ventilation, there should, of course, be some system In every schoolroom by which air can be introduced from outside and then allowed to escape without using the windows, which cannot always be depended upon on account of drafts and storms. These and many other points should be insisted upon by parents.

WHY SILVER TARNISHES. Although every housekeeper is painfully aware of the tendency of silverware to part with its brilliancy and become tarnished when exposed to ordinary atmospheric influences, many do not know that the cause of the tarnishing is the action of sulphur in the air. Unless frequently cleaned, the surface of silver will become black in the course of a few months. The best way to keep silver bright, without the necessity of cleaning, is said to be to coat the surface with a thin solution of collodion varnish diluted with spirits of wine. After being applied with a soft brush the spirit evaporates, leaving a thin, glossy, transparent Him on the polished surface. Warm water removes the varnish. Tarnished silver may be restored by careful rubbing with a soft cloth wet with dilute solution of potassium cyanide,—one ounce to a quart of water, —followed by rinsing. A WIRE FENCE CONVENIENCE. A wire fence always presents to those who understand the “power” of its barbs a formidable appearance, and, in truth, is an unpleasant affair to cross, either by climbing over or crawling under, -or between the strands. Happily, however, the accompanying illustration shows a convenient and safe arrangement whereby such barkers may be crossed as often as desired, and that without any

tension on the wires being lost by cutting a gateway. It is simply a double stepladder, and can be constructed by any one at all handy with tools in a short time, the railing consisting of gas pipe, the lower ends of which should be deeply inserted into the ground. Where a wire fence has to be crossed frequently in somo out of the way locality this device is of great value. BOOH IN THE WEST. It is not generally known that there arg in the United States unutilized areas of land to the extent of 600,000,000 acres. There are times when one Is apt to think that the country is getting a trifle crowded, and one welcomes the opening of little tracts of a few hundred thousand acres as affording opportune relief to a condition of almost dangerous congestion. But all Europe does not possess the area which is Included in the arid region weet of the Mississippi. There’s the rub —it 1* an arid region. But in these

days of vast Increase In the employment of irrigation, the solution of the problem of congestion appears. This tremendous expanse of territory is capable of supporting a population of 50,000,000 people. At the increase rate of only 5,000,000 or 6,000,000 in a decade, It will be a long time before the population of the country has reached 126,000,000. But the preparations must be 'made to accommodate a population roughly estimated by these figures. CURVE RULE INVENTED. In the picture is shown an adjustable curved ruler invented by Prince Anareas Gagarin of St Petersburg, Russia, which will be found very convenient in drawing schools, architects’ offices and for designers’ use generally. With the aid of this ruler it is not only possible to draw a curve of any radius, but also to measure curves accurately, a gauge being provided to indicate the circumference or diameter of the circle formed by a continuation of the arc. The frame of the ruler consists of a series of pivoted levers connected with each other in such a manner that when the adjusting screw is turned the arc of the circle is varied accordingly. The face of the ruler which maintains

the curve is a steel strip suspended from the levers in such a manner as to allow free play between the ends. The adjusting gauge has a sliding indicator attached to the end of the steel strip, and as the levers are moved in either direction this indicator moves correspondingly to show the size oi the arc.

RUBBER FORESTS IN VENEZUELA. Along the river Orinoco the caoutchouc, or rubber, trees are scattered about in families, in forests composed of many other valuable woods. The men engaged in the collection of the raw rubber make entrances into the thick forest on the banks of the stream, and then open tracks penetrating the leafy wilderness. They find from 100 to 200 rubber trees along the course of each of these tracks, although the distance seldom exceeds two-thirds of a mile. The milk, which is white when it issues from the tree, is coagulated with smoke into dark balls, weighing about 44 pounds apiece. Recently the planting of rubber trees has become a considerable industry in Venezuela.

CAKE DISH AND CANDLE HOLDER. Mrs. Julia Alice Earl of Cincinnati has invented a combined dish and candle holder for use in connection with birthday cakes. It has a central vertical tube, with a second tuba coupled to the first one at Its upper end In such a way as to be easily removed. The second tube supports a senes of branches, which in their turn are provided with sockets to hold the candles. One advantage of the arrangement is that any one of the sets of candles may be removed at a moment’s notice, and thus one may have as many tapers as are wanted, or as few. THE SMALLEST WATCH. What is said to be the smallest watch in the worJd has recently been made. It Is so small that you could get four watches of its size on an area equal to that covered by a 25-cent piece. The watch was made at Geneva, where special tools were constructed for the purpose. It contains 100 separate parts and weighs one-thirtieth of an ounce, avoirdupois, The hands are, respectively, one-eleventh of an inch and one-twentieth of an inch in length. The watch has been valued at $1,250.

SCIENTIFIC NOTES. Improvement in Glaaa-Blowing. By employing compressed air, a Dresden manufacturer has lately succeeded in producing glass vessels of extraordinary size. Heretofore, it is said, concave glass could be blown into vessels having a capacity not exceeding about 26 gallons, but by the new process glass bath tubs and large glass kettles can be blown. Breoie Powder. The shining metallic dust that is used to produce the effect of gilt and bronze in wall-papers, printing, lithography, mirror and picture frames, fresco painting, and so on, has its principal source in the bronze-powder factories at Furth, in Bavaria, where this industry has been highly specialized. The material is “Dutch metal,” an alloy of copper and spelter. The larger the percentage ot spelter the more yellowish the alloy. Seven principal tints are produced, varying from golden yeltow to bright copper red. The alloy is first prepared in the form of leaf metal which is afterward ground into powder. ■ :• -

A STEP-LADDER.