SCIENCE NOTES.

Otago Witness, Issue 2300, 31 March 1898, Page 54

SCIENCE NOTES.

I. ■ Experiments on the action of Rontgen rays on vegetable life have hitherto mostly I lad to negative results ; but Signor G. ! Tolomei, writing in the Atti dei Lincei, is led to the conclusion that their action is identical with that of light. Ob exposing 1 to the action of Rontgen rays branches of I Elodea canadensis immersed in water charged 1 with carbonio anhydride, evolution of bubbles : took place as in the presence of sunshine or i electric or magnesium light. Tbe same siniij larity was observed in the effects on the S lower vegetable .forms, both Rontgeu rays and light causing retardation in the absorption of oxygen by Mjcoderma aceti, and in the evolution of carbonic anhydride by Sacobaromyces. Again, in their action on Bacilluß anthracis the Rontgen rays behave in tha same way as sunshine, but in a minor j degree : when a gelatine film was exposed for 2£ hours to the radiations from a

Crookes's tube, with the interposition of a z'.oc screen having au X-shaped aperture, the tetter appeared transparent on an opaque background. That tbs action was due to destruction of the germs, and not to the generation of any toxic quality in the agar, was proved thus : when a sterilised film was partially exposed to the rays, and subsequently brought into contact wifeh a stratum o£ dried spores, the spores began to germinate all over the film ; but when the stratum of spores was exposed to the rays, the screen with the letter X being interposed, and the film subsequently brought into contact with them, only those spores which had been promoted from the Rontgen rays developed, and tbe letter X wa3 distinctly seen. Signer Tolomei attributes the previous failure to obtain such effects to the short duration of the exposures. • . • M E. Wadswortb, of the Michigan School of Mines, write 3to Nature expounding a mechanical theory of the divining rod. He says :— "This vheory has been rspaatsdly tesfcod by me and shown to be- correct in the presence of my classes. Tha proceßs is exceedingly simple. Take an}' forked twig of a reasonably tough fibre in the clenched bands with the palms upward. The ends of the limbs" forming the twig fork should enter the closed fiats On the exterior side of each fist — that is, on the two sides of the clenched hands farthest from each other. When a twig is grasped ia this position iG will remain stationary if .held loosely, or with only a moderately firm grasp, but the moment the grasp is tightened the pressure on the branches will force the end of the twig to bend downwards. The harder the grip the more it must curve. The earva*urs of the twSg is mechanically caused by the pressure of the hands forcing the limbs to assume a bent and twisted position ; cr the force that causes tha forked limb to turn downwards is furnished by mu?cles of the haeds, and not from any other cause. The whole of the secret of the divining rod eeema to reside in its position in the hands of the operator, and in his voluntarily or involuntarily increasing the closeness of his gra?p on t,he two ends of the branches forming the fork. If the above conditions are fulfilled the twig will always bend downwards — water or no water, mineial or ro mineral. Anyone can be an operator, and any material can be used for the instrument-, provided the limbs forming the fork are snfficiecfrly tongh and flexible. It can be easily understood how an ignorant oparator may deceive himself, and be perfectly honest in supposing thai some ccculb force, and not his hands, causes the fork to curve downwards." ••■ A plan- for constructing an underground pipe that is not to be subjected to a great pressure, has been employed in France with satisfactory resuUs. A trench is dog, and the bottom levelled with cement mortar; an inflated rubber tube covered with canvas is then laid iD, and cement is poured around and over it. The trench is then filled in, and the tube deflp-ted and withdrawn. It is said that Gin pipe* have been made of hydraulic lime and. sand at a cost of 22c per yard. ■ . • Ifc sounds almost iucredible that one bridge should be removed and a new bridge ; substituted for ib, both operations being accomplished within an hcur, yet such was recently done in Eeglaad by the Great Northern Railway Company. They have ; been widening their line between King's ; Crosa and Huntingdon, and it became necee- I sary to have an improved bridge r.ear Hatfield. To effect this the ' traffic was ' temporarily suspended, and with eveiy I necessary appliance in readiness, the old ! iron bridge south of Hatfield, over which | ran four lines of rails, was removed and re- j placed by a new iron girder bridge, the work ] being completed in about 50min. This feat, remarkable as it is, has been surpassed by the Yankees. Tha Pennsylvania?. Railroad Company the other day removed the old bridge over the Schyulkill River, and replaced it with a heavier steel structure, 242 ft. long and 25[b wide. The removal of tha old bridge was completed in 2mm 28aec. • ■ The influenza epidemic now prevalent, in some districts at least, differs in its character from those from which we have suffered in previous years. It has long been recognised that the disease may prasent at Jeas'u three distinct types, according to whether it attacks most severely the respiratory, the nervous, or the digestive system. In the earlier epidemics in recant years the majority ot cases belonged to the first type, and many deaths were caused by bronchitis asd pneumonia. Later, the prevalent type was the nervous, and men were left in a i cocdition of mental and physical depression j which for many months greatly limited their ] activities, and in too many cases helped to j fill the asylums. The present epidemic is remarkable for the very large proportion of caseß which show symptoms of profound

disturbance of the digestive system. The symptoms are in many cases so severe and pronounced that the most experienced physicians have in individual cases felt some hesitation for several days in rejecting the diagnosis of typhoid fey??. The fatal cases of this disease, which had beeu 40 and 73 in j the tivo preceding weeks, further rose to S8 i I the week ending Saturday, January j 3 29, a higher number than in any week sicce ! March 1895. Ot these SS deaths, 20 were j of persctsss under 40 years of age, and 25 of j person's aged between 40 and 60 years ; white 43, or nearly half the total deaths, were of persons aged upwards of 60 years. Influenza continues to be.much more fatafly prevalent in South London than in any other part of the metropolis, especially in Battersea, Wandsworth, and Camberwell. In Kensington also the disease appears to be very fatal. — British Medical Journal. • . • The following process, invented by Mr Rubbineck, for metallising wood is thus described by L3S Mondes :— " The wood is first immersed for three or four days, according to its permeability, in a caustic alkaline lye (calcareous soda) at a temperature from 75deg to 90deg. Thence it passes immediately into a bath of hyposulphite of calcium, to which is added, afcer 24 or 36 i houre,- a concentrated solution of sulphur in caustic potash. • The duration of the bath is about 48 hours, and its temperature is from 35deg to 50deg. Finally the wood is immersed for 30 or 50 hours in a hot solution (35deg to 50deg) of acetate of lead. The process, as may be seen, is a long one, but the results are surprising. The wood thus prepared, after having undergone a proper drying at a moderate temperature, acquires under a burnisher of hard wood a polfsbed surface, and assumes a very brilliant metallic lustre. The lustre is still further increased if the surface of the wood be first rubbed with a piece of lead, tin, cr zinc, and be afterwards polished with a glass or porcelain burnisher, j The wood thus assumes the appearance of J a true metallic mirror, and is very solid and i resistant." \