Science Notes.

New Zealand Mail, Issue 995, 27 March 1891, Page 6

Science Notes.

The mechanical difficulties attending the introduction of the storage-battery system said to entirely overcome;, arid tile sole, question now to tie considered is tliat of its economy iu comparison with other systems of traction.

It is proposed to use an artesian well in Paris for running a central electric station. The well is 2250 feet deep and discharges 215,009 cubic feet of water per day, with a force that throws it to a height of 114 feet. Turbine wheels will be used.

As an illustration of the remarkable suspension of vitality known among some of the microscopic organisms, it is said that mi* croSmes may lie during entire geologic periods in such k .rock ds chalk, And ybt retain thS power of developmeiiti

Measurements of 21,000 children in Saxony show that the boys are a small fraction of an inch taller than the girls up to the eleventh year; but that the girls then become taller until the sixteenth year, when the boys again surpass the girls in height.

Even yet we do not seem to have reached the limit of human ingenuity in the matter of automatic machines. The very latest automaton is said to be a boot-cleaning machine, which performs its appointed task on the dropping of the usual coin into the inevitable ‘slot.’

* Electrical Flat Ifdns ’ ate ndw in tiie market-, oiS more tjorrebtljr; irdns heated By the electric currehfc. The iiiterior contains ii Bet df coiled wires; through which the electric current passes and heats the wires fed hot. ThS latter are arranged between protecting sheets of mica and asbestos. By turning a. Switch thb flat iron at once heats up ready for lise.

Paper tubes are now being used as conduits for electric cables, water, gas and other purposes. The method of tlieir manufacture is interesting. The width of the paper is equal to the length of a given pipe. The paper is first run through molten asphalt and is then rolled upon a mandrel of wood, the size of which determines the diameter of the pipe. When cool the inside of the pipe is covered with a certain kind of enamel and the outside with a composition of bituminous lacquer and sand, and it 1s said that a oom-.. paratively thin pipe will stand a very powerful pressure.

Selenium is not a metai, but belongs to the sulphur group Of elements. We must mention, however, the wonderful property by which its electrical conductivity varies according to the amount of light falling upon it, just as the chemical relations of silver are altered by the same means. By this power Professor Bell was enabled to Construct an optical telephone, and actually transmitted words and sentences between two distant points Which were not connected in any way, except by a beam of light, which faithfully carried the vibrations of his voice to a selenium disc, by which they were transformed into electric energy and reproduced in an ordinary telephone. Whether we shall be able to see our friends at a distance, as we now talk with them, is exceedingly problematical ; but if we ever do so, it will doubtless be through this mysterious connection between light, electricity, and the element selenium.

Some time ago M. Zigang adapted the magneto-telephone of Professor Bell so a 3 to make it give out a continuous musical note of one tone. This was done by causing the vibrating plate or tympanum to make and break an electric current circulating in the coil around tho magnet. The current, thus interrupted by the action of the plate itself kept the latter in vibration as the hammer of an induction coil is kept in vibration by the intermittent current in the coil. The tone produced had the pitch due to the fundamental note of the plate; and it was possible to make a musical instrument by using several plates of different tones. But quite recently M. Zigang has been able to evoke a variety of notes from a single plate by touching it with a stylus at different points and so altering its vibration. He is thus able to play tunes on one telephone, and has in a measure produced a new musical instrument. ‘ ‘

A new development of the use of the phonograph, which promises to bring the instrument into the field of practical medical science, has just been demonstrated. Mr ! Ernest Hart lately suggested that the phonograph might with great sdvantage be employed to record the characteristic changes in voice sound which mark a variety of diseases. According to the British Medical Journal, this suggestion was acted upon, and Dr Felix Semon consented to select from his patients at St Thomas’s Hospital a few cases in which pathological varieties of phonatioa were present. This was carried out with great success, and at a recent gathering, at which a considerable number of eminent men of the profession happened to be present, the phonograph reproduced the characteristic vocalisation of some of these diseases with the most realistic effect. The whoop of whoopingcough, with the intervening cries of the patient, were as vividly reproduced as if the child were in the room, and ao also with the hoarse utterances of a case of stenosis of the larynx. The opinion was universally expressed that this new application of the phonograph to the purposes of diagnostic and clinical instruction constituted a solid gain for teaching, and probably for many other j purposes. It will be possible to reproduce a series of cylinders capable of use in every medical lecture-room and clinical theatre, which, at but little cost and without any difficulty, will afford to students and practitioners a lifelike reproduction of these characteristic sounds which no amount of mere word-painting can afford.