Science Siftings

New Zealand Tablet, 20 April 1911, Page 737

Science Siftings

BY 'VOLT'

Defective and Misplaced Teeth. Dentists make the startling disclosure that they can alter and enlarge the jaws of any child by simple means. and that they have found that the teeth themselves and their arrangement are the pattern from which the jaw takes its shape. Three people out cf four seem to lack in the proper development of the lower portion of the face by reason of defective and misplaced teeth and weak and ill-developed jaws. Utilising Old Rubber. The great increase in the price of rubber gives additional interest to ... the process of regeneration of waste rubber. The regeneration of vulcanized India-rubber consists in removing the sulphur, which was added in the process of vulcanization. The scrap rubber is assorted according to quality, and is treated either with sulphuric acid or with potash, for the purpose of destroying fibres of cloth, etc., and of removing the greater part of the sulphur. The material is then ground and washed. This regenerated India rubber is used only as an addition, in small proportions, to new rubber. The Age of a Fish. The age of a fish can be determined by examining the bony parts of its hearing apparatus. These increase in size during;"the entire life of the fish, each year adding two layers, a light colored one formed in summer, and a dark one formed in autumn and winter. The alternate layers are sharply contrasted and very distinct, so that there is no difficulty in counting them. The number of pairs of layers is equal to the number of years 'he fish has lived. By this means it will be comparatively easy to determine the rapidity of the growth of fishes, and the effect of fisheries on the population of.the sea. The Panama Canal. The mere mass of the concrete floors and side walls of the locks at Gatun, in the Panama Canal Zone, ought to be sufficient to give them great stability, but with a view to adding a further safeguard against rupture in the event, say, of earthquake shock, the Government engineers intend to reinforce the concrete by imbedding in it seven thousand tons of old rails. These consist partly of a light rail used during the era of French construction, arid partly of more modern American rails, which have been so badly bent that they can no longer be used for trackage purposes. A Pennyworth of Gas. N The price of gas differs in different localities, but taking the Manchester price of 2s 3d per 1000 as an average this will serve the purpose of our calculation. At that price 37 cubic feet, valued at about one penny, and weighing about ljlb, is a powerful factor. Its burning will generate about lib of water and about 19 cubic feet of carbonic acid. This pennyworth of gas will heat 30 gallons of water from 50 degrees to 110 degrees for a. bath, or it will in good kettles boil eight gallons of water and make tea for 64 persons. It will work a one-horse power gas engine for an hour, or lift a weight of 88 tons 10ft high, doing the work of six men for one hour. It will melt 101 b of iron, and make a casting in twenty minutes, which would ordinarily require two hours and 30!b of coke. It will braze a metal joint in two minutes which would require twenty minutes in a forge. If burned in a six-inch flue for ventilation purposes it will induce 80,000 cubic feet of pure air. It will give you a brilliant light of 50-candle power for nine hours, and in a good radiating stove will comfortably warm, a room 16ft square for an hour. It can easily cook a dinner for eight persons. Novel Bridge. The city of Toulouse, which already contains so many interesting monuments, has recently been enriched with a new and very remarkable bridge, called the Bridge of the Amidonniers (starchmakers), which spans the Garonne River, a little below the St. Pierre Bridge. The new bridge is the first large work of its peculiar type, which has been constructed in "France by Sejourne after the model devised by him for. the bridge at Luxemburg. This type of bridge is characterised by the association of two parallel masonry arches connected by. a floor of reinforced concrete. The Toulouse Bridge, the entire length of which is 730 feet, contains five such pairs of elliptical arches. The largest pair, in the middle of the bridge, has a span of 150 feet. Each arch of the pair is about 10 feet wide, and the two arches are separated by an interval of 33 feet. (The corresponding interval in the Luxemburg Bridge is only 20 feet.) By allowing the transverse girders of the concrete floor to project beyond the arches, the builder has obtained room for two overhanging walks and parapets, each about 10 feet in width. Thus, although the combined* width of the two masonry arches is only about 20 feet, the total available width of the bridge is about 70 feet ! This method of construction results in; great lightness of appearance and an economy of ■ material and, money which cannot be obtained by any other system now in use. : .