SCIENCE NOTES.

Otago Witness, Issue 2808, 8 January 1908, Page 76

SCIENCE NOTES.

— The new Government magnetic observatory at Eskdalemuir, Scotland, has been erected at a cost of £20,000. It is 56 miles frorr: Edinburgh, and 28 from Hawick. The magnetograph house is underground, and the seismograph -.is mounted upon -a pier •having its foundations upon-the solid "took, which was, 'found -20ft below the leve-1-of -the _ ground " r' ' ".^ n -^jTsges u keep air pujre ( < remarks a Scientist, because jtheyj, leaves^ djfeePßipqse, • cay*%onio acicl. '' Tne" volume o£ the carbolnio Exhaled by a t . human being in 24- hours is roughly estimated at lOCfgaf. If a* singie tree of moderate 'size were growing where «v -dozen, or eveii as many as 20, men were sleeping, the purifying action of its 'leaves would ensure that the air was "kept* quite fresh.

— -Professor Otto N. Witt, of Charlottcnburg, now asserts that the latest experiments, of Professor Ramsay. showth at unde? the_ influence of the energy contained in radium emanations, well-known elements like copper can now be concerted into others just as well known. This prov-es thai 'the • ancient ' alchemists were on the right track. Four years ago Professor Ramsay discovered that radium emanations changed to helium, and later 1 that this is- the' source of all the inactive elements. Latterly Professor Boltwood, of Yale, has shown that a new element exists in the uranium minerals, , where radium is, found, and which »s the parent of jadium. This new element gives of? both alpha and beta radiations, produces no emanations and resembles thorium. lonium is the name proposed ' for this substance.

— Irop cloth is used largely to-day by tsilors for making the collars of coats ses ' fashionably, jit is manufactured from steel wool, and has the appearance of having been woven from horsehair. Wool whicn ■' never saw the back of a sheep is being < largely utilised on the Continent for'making men's suits. It is known by the name ' of_ limestone wool, and is made in an elec- ' trie fiyrrtaoe. Powdered limestone mixed ; ,with a certain chemical is thrown into- the furnace, and after passing under a furious blast of air is tossed out as fluffy whiti . wool. After coming from the furnace the ' wool is dyed and finally made into lengths of cloth. A pair of trousers or a coat made from this_ material can be burned without permanent injury, and is as flexible as cloth made from the sheep's wool. — One of the most wonderful archaeological discoveries of modern times has just j been reported from the coast of Tunis. While some sponge divers were cruising on the northern coast of Sfax, one of theirnumber who had gone to the bottom suddenly found himself amid the columns- and fallen monuments oi some great ruined city on. the bed of the ocean. At first he thought he was the victim of some remarkable mirage,- but as he proceeded further, .incredulity gave "place to 'certainty. Ho dived again, and found that he was surrounded by the of a- great" temple with nraxble and btonze • statues in prbfu- > sion. I Large numbers of pillars are" istill standing, "and one.or*\two of the statues, were "aised and taken to Sfax. The di-s-coverers communicated the discovery to *he French and Tunisian - ''authorities, and a concerted effort Is, ,to. be -made to get vp as much as "possible of the sunken city.

— I-j; is announced that a~- French.- irjvdiator ] Afest 'discovered a cheap and easy process by means of which;, thread, similar in texture to cotton or linen and possessing great •strength, -can be manufactured from paper. - No details 'of <he method' of production i are 'vouchsafed, but the' thread is stated i to' 'be suitable for a variety of purposes, such as dress materials 1 for ladies' costumes, being- impervious to damp and non-inflam-mable, it can 'also- be used for the inanu- i fucture of bags, towels, "hats, and so forth. It is claimed that the thread!. ,can be jnade i at a" cost-of-90 per cent.* 'below,' that linen. i*nd' some -'60 ' per 'cent. ' less than.. that off j cotton:' "■'■►'' '"'' -ri ' j ' | ' — Dunnite, 1 the newest arrival in the field i of explosives, the invention of Major Dunn, of the United States Ordnance Corps, .s 6aid to'- be the most', powerful explosive -known. Heretofore this distinction has been held by shimose, which originated in Japan. In recent tests of dunnite at Sandy Hook it is said that 'the very best sin or ■ 6in armour plates that could be obtained were used as targets. The result of every shot was the same. The armour plate was smashed into thousands of small pieces by the impact. Penetration is' not necessary, the impact being such that the armour is shattered intd countless pieces. The oqtn--position of shimose is known to all the word over, but that of dunnite is a secret held by the, United States alone. ' < -"Mr W L. M*Atee communicates to Science the results of an interestine experi--ment to ascertain the number /of things that live or move on this earth. He took a census »f fcwo plots of four snuare feet of carth — one "plot on. a forest floor, and -another in a meadow. ' These plots wers examined in November and March respectively. Everything on the surface of these plots and the ground itself to the depth : a bird can easily, scratch was removed. There were obtained from the four square j 'feet in the woods altogether 112 animal ■•terns. In addition, there were 194- seeds i or fruits Assuming that the plot in oue?tion wa-s in no way exceptional, the analysis indicates that on the average there ajjei present on ear-h Here of forest floor in the, locality 1.216.880 animals of the kind specified and 2,107,810 fruits and seeds. From the four sqaa-re feet" of meadow were col- 1 lected 1254 animal objects and 3113 seeds The averages per acre for n>eadows, there fore, are— Animals, 13,654,710; and seeds, 33.822,745. The curious point about the estimates apart from their magnitude, is the wide discrepancy between populations of wood and meadow. ' — Thomas Godfrey, a famous JJineriean . mathematician, was a,' glazier. 'He seemed Ho be on4 -\>f the "most' singular phenomena . fhat\ever appeared 'in the learned world. One Jday. while at work at his trade in I Mulbery street, a girl came to a pump and i filled a nail with water, which was left upon I thfe sidewalk. The sun's rays were Te- ! fleeted from- Godfrey's' glass to the pail of j water, a«d then to his eve. thus completing: : a triangle. This is -said to have suggested • | to the glazier's mind the idea, which in 1 3730 became the basis for , the doubje 'rej *s*>otihc: sea cjuaclrant. Prior to this time English mariners had been using Davis's How to ascertain their latitude at sea. but j j; t could not. "be, adjusted^ in a storm r Godi Prey 'eavo' the subject, careful study, taught j Himself Latin in order to, read Newton's "Princinia." and endeavoured to have th« value of his invention recognised i*i Eng- j

land. While thus engaged he determined to have the device tested on a ship bound ' for the West Indies. In Jamaica the quadrant was exhibited, or presented, to an English sea-captain. Thus the important discovery came into the possession of Badley, a mathematical instrument maker in London, whose name it usually bears, in spite of the long exertions of -influential Americans •of the eighteenth century to hi^ve Godfrey's claim established. ~ u — Metebr trains are thp luminous cloud like forms seen after the.,flight of a meteor, which usually persist some time after the incandescent nucleus has disappeared. Professor G. O. Trowbridge has collected most 1 ' of ' the evidence- given by past observers, and discusses the data with the object' of deducing information concerning the physical constitution of the upper -atmosphere. It is found that meteor trains seldom, if ever, occur at , altitudes below 4-5 miles or over 65, the usual height being 50-60 miles. In this zone^ there appear to persist certain conditions favourable to the production of luminous meteor trains. As we -know; that the most' important "condition of , a gas respecting- the production of electric I discharges is its pressure, it seems possible I that the suitable degree of rarity is present at the above-mentioned altitude. As 1 many of the observed trains were visible I for 10 to 20 minutes, the phenomenon maybe regarded as a gas luminescence ; sund this i view is supported by the three facts — (1) the rapid lateral diffusion, amounting to as much as 100 metres per minute ; (2) the \ great volume contained within the boundary of the train, usually several cubic miles ; ! (3) the observed spectrum, consisting of a i few bright lines. Moreover, the rate of ' decay of the glow appears to be nearly . the same as is found in laboratory experi- | merits, especially in the case of the electrodeless ring discharge. — Knowledge. — The risks of explosion in flour mills are discussed in Knowledge and Scientific News. Mr S. F Peckham calls attention to the j occurrence of dangerous dusts in other facj tories.. After the terrible explosion in 1870 , in Minneapolis, in which three flour mills x were destroyed, a simple apparatus was devised^ by Professor Peek for testing the ,' explosibllity of the dust, and it was demontrated that the ignition of- 2oz of -flour in a box containing two cubic feet of air would I cause an explosion of sufficient force to raise two men standing on the lid of the box. Hence a sack of flour ignited in 4000 cubic feet of air would be .-apable of throwing 2500 tons to a height of 100 ft. The right proportion of air to dust is neces^ sary for an explosion, just as in the case I of mixtures of coal gas and air. With this ; apparatus Mr Peckham has shown that the dry dust in wood-planingr factories can be made to eiplode as readily a§ flour, and that, in fact, any dust that will burn maybecome a sourse of danger. For instance an explosion in a confectionery works in New York was traced to the- svgar 1 powder, whilst' dry -soap dust was found to -be responsible for a terrible fatality in a 'soap factory. Hence it is of the utmost importance that no dust should be allowed to accumulate- in any factory where .it is possible to prevent if doing so,. ' .