NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

New Zealand Herald, Volume XXXIII, Issue 10319, 19 December 1896, Page 4 (Supplement)

NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

A NEW INCANDESCENT LAMP.. , \ : 1..',; /: . <• A nkw incnndesceut lamp Invented in Germany coiMista of an • incandescent plafco, connected ab.eaoh side by a platinum wire and inserted in a glass bulb and the ail* extracted, as in , tho ordinary, incandescent lamp. The " glow plate" is manufactured of pure utipressdd and hygroscopic asbestos fibre, cub into strips of about three millimetres thickness and about six centimetres long. Tho resistance of the glow material is much greater than tho resistance ■ of carbon, so that the life-giving surface can be made much greater than in ordinary incandescent lamp?. BUILDING ON SOFT GROUND. ; When it is nectary to erect a heavy building upon soft ground, more solid ground underneath muse by somo means be roached ; and there aro two courses opoti: oither to oxcav'ate'the full depth, or to drive pile?. If the soft ground is of but moderate thickness—say loss than, 20 feet—trenches may bo cub under the avails down to the solid and filled up with concrete. If the soft ground is milch less than 20ft, it may be excavated entirely, and either used ns a cellar, or filled up with concrete or hard dry material. If the soft ground is more than 20ft in thickness, piles must bo used. The term " piles" is hero employed in the very broadest sense, and may be taken as including pillars of timber 1 , iron, stool, concrete or brickwork. An ordinary timber or iron pile needs no description. It must be sufficiently long to roach the solid eround (timber piles may bo obtained up to 70ft in length), and tho pilos must be sufficiently numerous to carry tho weight. Timber piles should be cut off at t.he ground-water lovol. Across the tops should bo laid crossheads either of timber or of steol, and upon those a bed of concreto covering tho wholo site should bo laid. Concrete or brick pillars may either bo oxcuvatod for and built solid; or may bo builb on a cutting ring and forcod down, tlio matorial being taken from the inside, and the spaco nftorwards filled with concrete. The former method will servo wlion there is little or no water to contend with; the latter when it is cheaper to use a grab than to pump.— Building World. TAKING OKI' QUANTITIES AND PREPARING ESTIMATES. To bo able successfully to tako off quantities from drawings, and prepare estimates, threo things are necessary—a knowledge of arithmetic and mensuration ; a sound knowledge of the details of building construction in all trades; and practical experience in tho application of the two foregoing qualifications to toko off tho measurements and stating them in the manner usually adopted and understood. Tho detailed dimensions are first) of all taken off tlio drawing, and written down in columns, with an abbreviated description of tho work to which the dimension refers. When this lias been done for all trades, tho next operation is ?([ wring tho dimensions, to obtain eithor the cubic or superficial measurements resulting from each set of dimensions. Tlieso results aro oollectod together in tho abstract, for oach trade; the total collodions in each abstract aro thou placed in their proper order in a bill of quantities; the bill is ruled so that a prioo and a total may bo placed against eaoh item; tho sum of all the to&als will givotl.o total proposed cost of all tho work mentioned and desoribod in the bill of quantities. This is called the estimato,— Building World. DISCOVERIES IN ASTRONOMY. Astronomers have boon exceedingly active during the last few week.* in making discoveries. On September 23 a new minor planot was discovered ac Heidelberg. Tlion followed tho dhicovorv of a new comet by Signor Giacobini at Nice, and of another comet by Mr. Brooks, of New York. Professor Holdon, of the Lick Observatory, discovorod a bright prominence on tho terminator of Mars, but he has not yet found whether the elovation was a mountain or a cloud. Later on, Dr. See, of Lowell's Observatory, found now foatures in the system of Sinus, and last of all, Mr. Bailey, astronomer at) tlio Arequipa Observatory, lias discovered a new double star. DKLHIIUM TREMENS. " It is said," remarks the Medical Times, " that 95 per cont. of visual hallucination in delirium tremens consist of snakes or worms, in one form or another. Dr. Davis has been investigating the subject in the alcoholic wards of Bellovuo Hospital with the ophthalmoscope, and has brought out some interesting facts. In every ono of tho sixteen cases examined, tho blood-vessols of tho retina wore found to be abnormal. Instead of being palo and almost invisible, as in their ordinary condition, they were dark, almost black, with congested blood. Tho blood-vessels of the retina, which aro so small and semi-transparent in health that they are not projected into the field, of vision, assume such a prominence that thoy aro projected into the field of vision, and their movements scorn like tlio twisting of snakes." A NEW SCIENTIFIC! ASSOCIATION. Tha fact that " the American Association for the Advancement of Science will meet j novt year at Detroit, on tho Canadian frontier, and will adjourn to Toronto to welcome tho British Association to American territory," coupled with tho similar fact that tho French and British Associai tions are to meet rospoctlvely at Boulogne J and Dover In 1899 for the purpose of exchanging compliments acrosj the Channel, suggests to Science a plan for an "International Association for tho Advancement of Science." It Hays: " The first year of the twentieth century is opportuno for the first mooting. Many men of scienco will be in Paris, and if London or Berlin should seem more eligible they could easily gather in ono of these cities. Tho preliminary arrangements could readily bo made by the American and British Associations in 1897, and tho final arrangements by the British and French Associations in 1899." RAIN EXPERIMENT. _ L. Errofa describes in Torro otCiol a vory simple manner of producing a rain, not of wator, but of alcohol, and tho winds which accompany its formation. That ho is by no means the first in tho field does not make his experiment loss interesting. A glass cylinder about f| inches high and 4in in diameter, is half filled with alcohol of 92 per cent. Tho cylinder is covered with an ordinary china saucer and slowly heatod in a water bath, so that the wholo becomes warm without the alcohol beginning to boil. Tho vessel is then taken out of the bath and placed on a table. Vapours soon begin to condense on tho saucer, clouds form, and tiny regular drops fall down in vortical linos into the alcohol. The drops have an. average diameter of 40 or 50 millionths of a millimetre, but thoy vary in size. Tho rain continues for half an hour. The upper part soon clears, and tho condensation takes place somo distance below the saucer; thus we have the ocean, the clouds abovo, and tho serene sky higher up still. If, aftor heating the vessel, tho hob saucer is suddenly replaced by a oold ono, storms can bo observed. As ono sido of tho oylinder will nob rarely be a little colder than the other, ascending currents can often be noticed on tho ono Bide, descending on the other. If tho warm part is cooled, the currents change direction. Tho arrangemont lends itsolf to other experiments,— Engineering, THE EFFECTS OF THE X RAYS, A young man who had been used for about four weeks as an object for demonstrating X rays phenomena discovered to his surprise that his skin was peeling off at tho places which had boon exposed to tho rays, causing sores in somo places. He also began to lose his hair, and is now threatened with promaturo baldness. SUN-SPOTS AND THE WEATHER. Do the sun-spots affeqt the weather of tho earth? Professor Norman Lockyor and other er»inonb men of wienae believe they do, Oil' the other hand, ..there are some who repudiate the,notion, Those, bowever, seem to expoct that the influence, of the sun-spots should bo felt everywhere on the earth's 'surfaco in the Bume way. Haying regard , to the instability . and variability of the weather, this is probably an error; and, as Mr. A. B. MacDowall, F.R. Mot. S., has recently' pointed oub in Nature, we should nob expect to find a similar effect everywhere, bub rather " an averageeffocb, a tendeiioy, a preponderance." A study which he has made of the meteorological statistics of Bromen seems to show that the, sun-spots do affect the weather there,, Mr. MaoDowall formerly showed thab ,_tho.iweather of Greenwich was apparently influenced by, the sun-spots. j