SCIENTIFIC NOTES.

Te Aroha News, Volume I, Issue 43, 29 March 1884, Page 3

SCIENTIFIC NOTES.

Amonu the new applications of cotton is its use, in part, in the construction of houses ; the material employed for this purpose being the refuse, which, when ground up with about an equal amount of straw and asbestos, is converted into a paste, and this is formed into large slabs or bricks, these acquiring, it is said, thehardnessof stone, and furnishing a really valuable building stock. It is also proposed to substitute, in the general manufacture of rope, cotton for hemp, thus not only saving about fifty per cent., but obtaining a preferable article for all shipping uses — cables, bolt rope, halyards, tow ropes, hawser, tackle and falls, hoisting, &c.

Successful tests have been made with an improved construction of elevator brake, the peculiar feature in this case being that the air is compelled to act as a brake, giving a yielding force and stopping the car readily but gradually. One of the tests consisted in putting on much more weight than its given capacity, raising it to the top of the building, then severing the supporting cables ; the car, under these circumstances, with its heavy load, unsupported, dropped only six feet, when it stopped gradually, in a descent of four or five feet, and remained stationary. The cables were again attached and other tests made, the car making fast or slow ascents and descents as desired.

Recent experimentsshow the photography of sound-vibrations to be a practical process. A small, thin platinum plate was attached perpendicularly to a thin iron plate, which, as in the telephone or phonograph, was fixed on a wall piece and vibrated to sound. With a solar microscope an image of the platinum plate was focussed on a screen, after which a prepared photographic plate Avas quickly moved across, in the plane of the screen, by a strong spring, while the mouthpiece was spoken to. A bounding line between light and shadow was thus obtained on the prepared plate, forming a curve closely corresponding to the sonorous vibrations— simple curves for vowels, complicated ones for consonants.

A communication of much interest has been made by Herr Bissinger to one of the German scientific associations on the magnetization of steel and iron bars when broken in a testing machine. The phenomenon, he says, is not brought about by the elongation that accompanies the breakage, but is produced at the very moment of breaking, the two halves being convei'ted into magnets of equal strength ; the breaking occurs with a loud noise and strong shock, so that the resulting concussion might possibly be considered as the cause of the magnetization. The bars were placed vertically in the testing machine, the south pole forming at their upper extremity. The different tools and objects of steel in the vicinity of the bar at the moment when it breaks also become magnetised, though to a much less degree.

An improved construction of steam boiler has recently attracted attention, the design being to insure greater durability and to generate steam with a minimum amount of fuel. This is accomplished by providing a water chamber at the back or bridge wall of the furnace, this being supplied with circulation tubes, which extend into the fire box and combustion chamber. By this method, it is claimed, a safe, inexpensive, and durable boiler, of compact form, not liable to become injured by expansion and contraction, is secured. Each tube is independent, being thus free to expand and contract, according to the heat it may receive, without affecting the others. A continual circulation of the water through the tubes has the effect of causing the sediment to fall to the bottom of the water chamber, where hand poles are provided for its removal.

The Red Sunsjtts.— Henry J. Slack, F.G.S., F.R.M.S., writing in "Knowledge," says :—" Much interest has been excited lately in the character of atmospheric dust, in the belief that we have been passing through a meteor stream of very minute bodies, which may have caused the splendid after-glows following sunsets, and the similar appearances before sunrise. Besides the investigations of Captain Noble and Mr Mattieu Williams in this country, similar examinations of atmospheric dust on the Continert have led to like results ; and it was stated in the French Academy that there was reason to believe an unusual quantity of fine meteoric matter fell in the second half of November and the beginning of December. Collecting snow as soon as it falls in the open country, letting it thaw in a perfectly clean vessel, and viewing 1 the matter deposited under the microscope, seems the most successful way of catching these particles, free from much admixture ; but at any time, in ordinary localities, the air is found to contain a multitude of small objects. In and near towns the quantity is much greater than away from them in open country places, or at considerable heights, far from habitations, where the air is often pure. Snow, however, in such places, would be likely to yield meteoric dust."

We have been told many times lately how hard is the life of our fishermen ; still, we know when they do make a profit it is always a "net "profit. In Dunedin, 20,000 shares have been applied for in the new Accident Insurance Company, 10,000 in Christchurch. In one day 3,000 shares were taken up in Wellington,