SCIENCE NOTES.

Otago Daily Times, Issue 12248, 11 January 1902, Page 8

SCIENCE NOTES.

— A flume ,6ft wide and sft high should ho built of ljin plank + x u scantlings, 6 x 8 or 6 x 10 lumber for sills. A 16ft bra of such a Hume would require to construct it between 760 ft and 800fl of lumber, being 47Jft to 50ft to the linc;,r foot of ilumc.

—An interesting acoustical experiment has been noted recently in tho Physical Review. A light hollow cylinder had ono end closed by a Ihin disc, tho othor end boing left open. This cylinder was placed in :i. stationary sound-wave, with its axis at right angles to the direction in which the wave travels. Tlie source of sound in the experiment was an organ-pipe. It was found that the cylinder moved in tho direction of its axis with a. certain velocity, and the motion was observed to bo independent of tho pitch of the note. A curious result ,was obtained by fixing four cylinders on a rotating shaft placsd with its axis of rotation perpendicular to tho wave-fronts. The sound-waves from the organ-pipes then caused the cylinders to revolve in a somewhat similar manner to the cups nf an anemometer, except when placed at the nodes. This novel phenomenon is a simple result of Bnrnouilli's well-known relation butween the pressure and velocity in a fluid. The air on the outside of the cylinder is moved to and fro ncro-s the ilisc, by the. soundwaves, while the air inside is undisturbed, tl>i.i3 sotting up iV difference of pressure on the two jides of the disc.

, —Cyanide is ;i compound of cyanogen with a metallic agent. Cyanogen is a colourless, poisonous, litjuofinhlo gas which has tho odour of almonds and burns with a purple, ilame. Cyanide of potassium is made by burning potassium, an alkali metal, in cyanogen gas, and is really a prussiate of potash. It is produced also in Mast furnaces in which ore is smelted, with coke or coal, and is prominent when kept dry, but decomposer rapidly in moist air. It crystallises in dry, octagonal blcc-kx, and is extremely soluble in waler. ll lias tlie odour of pru??ic acid and kindred bitter--11033 of tasto. Betides its interest to miners and _ metallurgists in the cyanide process, cyanido of potassium is also used in electrometallurgy and photography to a considerable extent. It will remove metallic oxides, the juicss of fruits, and indelible ink.

■ In opening the winter session of tho Bradford .Scientific Association, Mr T. Pawson (president) selected for his subject "Robbers and Murderers in the Vegetable World.' The competition and struggle for existence in the vegetable world was, he remarked, best illustrated in tho luxuriant life of the tropic?.! forests, where parasitic plants exhibited in a marked form their peculiar method.! of obtaining sustenance, fastening with firm grip on others, and using them Willi reckless indifference as instruments for tiieir own advancement in life. Having instanced the gigantic parasite, Rafflesia Arnoldii. Mr Pawson de.-cribed the habits of the mistletoe!, the broomrane, the toothwort. Insectivorous plants, he Enid, had, generally speaking, defective roots, and lived upon poor soil. Therefore, it was necessary for them to adopt- other methods of obtaining nitrogenous food. The Sundew was a familiar example of this species, and Darwin proved that it was nourished by nitrogenous material provided by tlio insects caught and digested by the leaves. The Tonus Flylrap differed from the Simdew in that, whereas the Sundew w.is provided with sticky elands on tho leaves, which held and folded over their captive prey, tiie Flylrnp was provided with very sensitive bristles, the slightest touch of which caused the leaf to fold up, the end in both cusps being the same. The peculiarities of many other plants were noted, the lecture being amply illustrated by lantern : elides and a, large number of specimens, : mounted and living.

- -The preliminary experiments for the now high-speed electric road between Berlin and Zos?en, in Prussia, leave substantially no tloiiht that a prodigious fpeeil will he reached, "provided the track and roadbed will permit. The actual conditions of operation in tlio running contacts, the regulating appliance? and the brakes, pro far mure serious subjects for consideration than tho mere power and efficiency of the motor.-; on wln'cli dcpcrvl the reaching and maintenance of very high speed. And most of all is it important that tho conditions of station operation when handling such rwflic as the purpose of the tests conto.nplates he accurately ascertained. . . .

The only factor in the worlc wliicli secmi soiiiow'r.at uncertain is the character of tho track and roadbed. Although these ;w constructed with tho. thoroughness to he e.Spected in a Prussian military road, grades up to 3 p?r cent, and radii o[ curvature even as short as 1000 metres can hardly he considered as unduly favourable to the attaining of transiM'tiuVnial speeds. This U the road in which the Kaiser is showing so deep an interest. It is .by far the most determined attack on the high-speed problem (hat ha.i yd been made on cither side of the Atlantic, and if skill and experience count for anything, success may fairly lie predicted.—Electrical World. —"K. K. Korli iPhysiknl. Zeil'ebr.) has found dial lightning conductors whoso connections have become imperfect through rusting or otherwise act, nevertheless, in quite an efficient manner in the e.'iso of a thunderstorm. This is, in his opinion, duo to the oscillating character of lightning disoliargcfi. Electromagnetic waves are produced, which act upon (ho imperfect connections (13 upon a coherer, restoring their conductivity for a. more or loss loiif; period. Lightning has hitherto been considered a continuous discharge, which often becomes apparently oscillatory by quick repetition. Tlie author employes a rapidly-revolving camera in order to test this question, but docs'not arrive at any definite conclusion, as the flashes photographed were all too distant.

--Death Valley, in Invo Co.. Gal., contains a torge number of mineral deposits that will ultimately he commercially utilised. These include borax, salt, and nitrate of seda. There is one bed of salt over which tho old road from Mohave to tho borax works is built that is five across. I'ora;: exists in beds in old marrhes nmf in deposits, of coleinanite in the bordering hills. Tlio nitrates are in the bordering hills. The valley has ono fair-sized living stream, FuriMce Creek, which provides water for the old borax work;,' and to irrisale 20 acres of alfalfa, from which a cutting wan made every month. TrP?s, except m.csqitite. could not be made to grow, the fierce heat destroying them.

--Sir William Church delivered an olo(jucnt addrcfs on October 1?. at the opening of the now Pathological laboratory in connection wish the Oxford University MuBftiim, wliicli has licf-n c-rrcM at n co»t of upwards of 510.000. Kir William raid it appeared to him that that day had boon most happily chotoii (or oponing the Pntholoßiral Department, for that day was bcini; celebrated the ciithlioih birthday of the N'o?tor of pathological research, Professor Yirchnw, mid Oxford could not in a moro woitlry way yiay ifs homage to fho veteran scientist. Jv.st at tlio time tl»at tlicir museum w.-.s being erected, Profffw Vireliow gave to (lie world his memorable work. "Die Cellular Pathologic." which placed pathology on a new foundation, and taught.them to regard pathological processes as the perversion of physiological ones, influenced by various disturbing agencies. Pathology ronltl not lie ftiijlicd without physiology. neitiier eoidd physiology in its completeness bo carri'-'d on without pathology, and more especially had this become manifest since ihoy liril been acquainted vvi'ii the part played by micro-organisms in the universe and the influence they had on living structure*. The day of opposition to the study ol the iiiituval sciences in the university had happily lons einee ji:is=cd away, and they were more nearly approaching thn ideal the originators of the museum had before thorn.

--Dr Motohnikoff, the well-known scientist, discussing the- question "Have Microbes Useful Functions?" gives o\prc?-ion to his opinion in the following terms:- • What could o,io say of the function of these varied growths'; Among invertebrate animals there were sonic covered with much more , copious growths than were found on tho human s!;in. On the southern ami western coasts of Knsrjand there was found in great numbers a kind of crab whose whole shell was generally covered thickly with vegetable srrowihs. Their use was obvious.

I They assimilated the crab to the marine vegetation, and made him invisible alike to hi? HKMiiips ami to his prey. No such iliMiicnitiiiiion could ln> given of Hip utility of tho mievnhci on the human skin. On t!i'c oilmm- land, t!i.' )!..r.\ of Hi.' oavily of tlio month !)ii : ,'iit render man n htvut. Everylii'ily bad noticed that wounds inside (lie mouth healed much womim , than those- in the. outer Am. Moistened by liio saliva, thi> win-mis nnnmed in contact with (he miprebfi and thoir mlublo products, which stimulated in a marked deiirco tho reap!ion fit tlit-human oipniiUiu. Thp spcrotious of the microbes attracted a Rrrat number of white blood-rorpu-'Cics. which cleaned thn wound, cleared it of microbes and mortified tii:v,ips, and >o favoured the prneoss of recovery. In tho lower part.' of the digestive system tliis function of microbes was loss important, Hip inuciious lncinbranp there being iiiucli more seldom turn. Hut, it was probable that thp acids secreted by many bacteria in thp small intestine rendered a real service by preventing Ihn development of cprlain oilier microbes which might impede digestion. This preventive function wa.s m:i!iifpftrd also in thp course of conflict between the human organism and miprobes of a very dangerous kind, and there wa'i reason to believe that in some cases tin , germs of .Asiatic cholera were rendered innocuous by tho no! ion of tlip microbes which they encountered in tho intcsiiuos. It had also hern contended by sonm aiithorilies that the miciobcs in the digestive eystpni played an important part in the digesting of food, mid that without them food could not be assimilated: but. the data available would lead rather to the general conclusion thai for the normal action of the human digestion the presence of the intestinal microbe was by no means indispensable. •