SCIENCE & INVENTION.

Nelson Evening Mail, Volume XLIII, 1 February 1909, Page 4

SCIENCE & INVENTION.

AN ELECTRIC CRADLE. v An Engineer in Chicago has had somo lively experiences in home life. He married a lady graduate in medicine, and later he found that when his wife was on her rounds the care of the baby devolved upon him. Finding this work interfering with his own professional labours, the engineer produced an ap- £ paratus for rocking the cradle by elec- ■ t-ricity. He had another switch connected with a phonograph, which as soon as * the cradle was set in motion played some = lullaby, a favourite of the little one, * and so sent him to sleep. The engineer has also constructed an electric apparatus which gives tho little recipient its - milk at intervals. j NEW USE OF ELECTRICITY. ( Printed sheets as delivered from the ' press frequently "offset" or smear from " undried ink. An electrical method of s preventing this has recently been patent- < cd. The sheets as they leave the press first pass over electric heaters and also ) ! over a conductor carrying a current of i | very high tension, from which a silent 1 discharge or "leakage" of electricity i passes to tho paper. The combined effects of the heat and of the electrical dis- ■ charge, together with the chemical action of the ozono generated in the air ; by the latter, "set" the ink so that it cannot smear. J?esides this, the effect of an'v frictional electricity already present . 1 on* the sheets, preventing their piling ■ properly, is neutralised by the discharge. INOCULATING THE SOIL. 5 Fresh information as to the expert- j ments he is carrying out in inoculating | soil with plant-nourishing bacteria was * given oy Professor W. B. Bottomley in I lecturing before the Royal Botanic Society of London. Onions wotered with the bacteria culture, said the professor, fc showed an increase of 39 per cent in * weight over those which had not- been ciety of London. Onions watered with the 'culture produced a much finer crop 5 than a patch not watered. "I won't say * definitely'," remarked the professor, "that inoculation is possible with every kind of plant, but I do believe that we c shall be able to say so soon, and that the •' experiments up to' date justify that anticipation." c COURSE OF A HAILSTORM, il A hailstorm followed the course of an electric transmission line in Vancluse, a France., last June. As reported by an a observer, this storm swept over an area about a mile and a-quarter wide and nine miles long. Tho storm started to >r follow a narrow valley in the side of a 1* mountain chain, but on meeting the electric line, which cuts at right angles across a series of such valleys the hailh storm joined it and followed it until 16 exhausted. The effects of the storm were most violent <-lose to the line and decreased toward both sides. Hail fell is near the line, rain on the edges of the *'» storm's path. Another observer reports that three balls of globe lightning appeared near" the cables at one point, 'g bursting just before the hail fell. There "■ seems to'be no doubt that the line conducted the storm, but probably the presence of the electric current had sonii*- " thin;*; tn do with it Further observation--. ]* on oli-rlrio rtnrm* in the same locality '• thr.v.v li,*-lil nil the occuri-en-P. ia WIND PRESSURES. •* ! . In .-IniU nit* the pressure of the wind on thi' huge Forth Bridge, nearly a qu-il-II t-er of a century ago. Baker, the great '-. English engineer, discovered that the >' pressure on large surfaces was relatively less than on small ones. This has remained unexplained until the recent exp?rt- ! > ments of T. E. Stanton at the National ie Physical Laboratory in England. Stane ton finds that when the wind blows against any large obstacle its intensity is unevenly distributed and that the lower i B [ pressure on large surfaces is due to what a '• may be called the structure of the v/ind, '* whose gusts are mote effective on small areas than on large ones. Owing to the "gustiness" of the wind tests made in ' laboratories with steady artificial currents are misleading. The resistance ofe fared by a structure to a natural air current in the open is 18 to 20 per cent greater than that offered to an artificial J "wind" in n laboratory test. The oxP pcriinents on which Stanton relies for his conclusions were made on flat surfaces ranging up to a hundred square feet, ex- , posed to actual winds in open air. * MEASUREMENTS OF LIGHT. Photometry or measurement of the intensity of light is becoming increasingly important. Once hardly more than a la- , boratory experiment it is now part of regular industrial procedure in the manufacture and comparison of various types of electric lamp. In comparing the lamp with the standard unit to ascertain its "candle power" the use of the human eye is obligatory in all practical systems hitherto devised. This is objectionable for the eye is subject to all sorts of faults; but attempts to substitute some form of measurement dependent on chemical action variation of electrical resistance etc., have been fail- • ures. These methods measure, not the light, that is, the part of the total radiant energy appreciable by the eye, but some other part of it, with different limits, dependent on the method used. A French physician, G. Fery, has b?en at- -. tempting with some success to cut off all | radiation not appreciable by the eye by I using absorbent liquids and then to measure the remainder in one of th." various clieniiea) or electrical ways aij ready proposed. A solution of acetate of copper of . proper concentration has j been found to s-jrve very well, and measuremeants of -the transmitted radiation < ' made with Boy's -radio-micrometer agree ] ' almost perfectly with those made with I the human eye. Tb; radio-micrometer ' is an adaptation, for purposes of deli- ' '

cate measurement, of the Crookes radio- > meter — the revolving mica vanes iv an ] exhausted bulb so oftsn displayed in the windows of oijticians. , ELECTRIC BRUSHES FOR SHIPS. An invention which should be of signal service to shipping companies, has recently been perfected, the ob3ect of which is the cleaning of the submerged portions of a ship's hull while afloat, so that the necessity of going into a dry dock, witb its attendant heavy cost and expenditure of time, is avoided. At the same time it enables thi vessel to be kept in the pink of condition so far as - ncr speed capacity is concerned, and the use of anti-fouling compositions can be dispensed with. The scrubber com- ; prises an arrangement of hogging-brush- j es disposed on a mat of battens m such | a way that they are used against the lie , of the bristles, thus flicking off the . acumulated deleterious matter in ad- , vance of their progress. These battens , are fitted at either end with powerful , electric magnets, which, when the scrubber is in use, cause It to chug tenaciously to the sid4 of the ship, so that there is fo possibility of the bdushes riding over the harder accumulations of mar-ne vegetation. The mat is worked over tho huf by means of cables passing round the ship and actuated by the shtp s !fncU P Tbe magnets, which have an aggregate gripping power of over one . rbHlhatThffullSing To- I e r or'ht is'effecte^ I under n£ con- , Hitlons The great advantage of this sys i f^fis ihat it B enables . vessel to be clean- , cd while moored alongside the qiw>, , fading or unloading, expedi .ous^ , £ tffi'cannel rlwd fn and |»-tonner in about eight hours a - irl^r^^^e^l^wiUij areat success; boot-topping the fast pUra I sure-craft plying on the nwr. The sides of these ships for about five feet be low water foul so quickly that th-ay ro nJre cleaning three times as oHon as the ' was to lay the ships ashore fo a t-ao ' for cleaning purposes Now the, arc ; -lectricjlly a ofVs The m intenan'ce » o^efrtVo^K^fapp^ces in every '■ harbour, especially in «»"«* ro^ IM,ie^1 M ,ie^ ' where fouling is very rapid, would o much to enhance the attractiveness of th" ports to the shipping commun.tj who are often compelled tp wait a verj one "me bfore a favourable opportunity 1 Ss to enable the hull to undergo the : ' much-needed cleanin*-. n a

The Impei-iiil Government says the London correspondent of the Melbourne "Ar^no" have yielded to the desire ot ihe" 13 .man Ci-tholiJ.-**, -expressed in both Housfs of Parliament, and havo promised tn brint- in a bill, probably next session, to relieve the Sovereijrn from the necessity of making the declaration against the Pope and # transubstantiation obligatory at the commencement of each reign. It will not be an easy matter, he continues, to draft a form of word- which will satisfy the militant Roman C'atlwli'-s on the oi|o hand and Ui.-* Bi.inan t'.itholics on ihe f.lhf-r h.".n<l. Outside the extremists ih.-r.* are n„i 100 people in the lonntiy v.-lio dosire lltr-t a Kins shall begin hlf*. i.i'/n wilh an act of insnh to hi? H.-/-iii.wi 1"";,t J,.-ili.- subject-. Hut there i*. :c civ lar"-" iii:ijni-ii v v. lin f:u,Miv a d.-,lai7ai,i,i "to the ■--fi"."-. t lb:." !!■■■ Ro\-■ii-ign is a Mil, •(■■'■■• nn-iiibi-i' <^|' theC'iini'ch of Knchinil. and ihul he reject.* the claim of any foreign prelate to exorcise jurisdiction in lh ; s ronntry. Colonel Sir Theodore Bi-inckui-tn, C.8., who is on a sporting tour in New Zealand, spoke thus to a newspaper reporter at Wellington on trout-fishi-itr hei-2 : — He had had some fine sport at Rotorua, wl'ii-h hp look tts a base lor fishing in the surrounding streams, and at Pahiatua, where he fished in the Makere. Trout there were in plenty, and the only thing now needful was a little attention to the rivers. At a small expense obstructions such as branches, fallen lugs. etc.. could he it-moved so that the land would be clear for lly-tishing. "At present/ h-' said, "you are liable on some .streams to losi three or four casts through gettiii-f th?m ent-in^bd." The quality of the trout was L'ccd in the stream Colonel Brlnckton fished in. but a little judicious culling would improve it. Overstocking was really the trouble, and if the pnor fish were netted out more room would bo given for the good ; on?s. More plentiful feed might aho be provided by introducing n wtnl ■ tvhifli was grown ou the lalfs in i Scotland. With this and a few more , rainbow trout ihe sport would h= p.'Ti