NOTES AND COMMENTS.

New Zealand Herald, Volume LIX, Issue 18236, 1 November 1922, Page 8

NOTES AND COMMENTS.

PETROL-DRIVEN' RAIL CARS.

Suggestions havo been made recently that -ihe New Zealand Railways Department should utilise petrol T driven cars for services on lines carrying only light traffic. The technical journal, Engineering, recently made reference to this system of transport. The petrol-driven Tail motorcar is a logical development of the Steam inotor-coach which was first introduced to provide increased facilities for a patronage which did, not warrant a frequent normal train service. The petrol car in its present form is a rather smaller unit than tho steam motor-coach, and in American and Cajiadian practice has. been developed more along the lines of an omnibus type of vehicle.. Operated by ono man, running expenses of these cars in practice are as low as 11 cents per carmile, compared with 1 dol. 50 cents to 1 dol. 75 cents per train mile for steam-driven trains. This low cost of operation, together with their notable utility in sparsely-populated districts, form their chief claims to recognition. Another point jn their favour is ease of manufacture, for these petrol railway cars can. bo assembled largely of standard fittings and equipment, which contributes considerably to low first cost. With a possible speed of. 50 miles an hour in practice; under Canadian regulations these cars arc not allowed to exceed 40 miles per hour. The first cars manufactured in Canada are in use on the Canadian National, the Candiin Pacific, and the Quebec Central Railways. One has also been supplied to the Delaware and Hudson Railroad, for use between St.-Lambert and' other Quebec provincial, points, and is reported also to b e g' v ' n g satisfaction. The Canadian P&cific Railroad is using -its first -petrol,driven car for suburban work, from Cote St. Paul in the industrial heart of Montreal to Highlands', a new suburb on the banks of the St. Lawrence, a run of about five miles. The petrol, car is particularly useful on such a route, Highlands being' a new and, as yet, little developed section whose transportation needs are well met bv a general utility car which.' carries both passengers ' and baggage.

.ATOMIC ENERGY. As an illustration of tho size of tho atom, Dr. F. W. Aston, F.R.S;, lecturiiig at tho British Association meeting, said that if a very .small aperture was made in the side of an evacuated electrio light bulb and molecules of air were allowed to stream' through' this hole at the rate of one million per second it Would take one million years the bulb was fttll'j the itom being so extremely small. It might bo thought" impossible to detect the effects of one, burt by the amazing delicacy of. modern physical apparatus this was actually attained by using atoms moving at extremely high velocities. Thus a helium atom thrown as an Alpha ray through a radio-active' substance might travel so rapidly that when it" struck a zinc-blend screen a flash of light was caused which was visible to the naked eye. Collisions between- unclear atoms were extremely rare, . but _ Sir E. Rutherford had shown that it might re; eult in the t>jtruction. of the nuclei® bit and change it into an atom of another element. This was the first real chemical transmutation of elements achieved. The possibility of such transmutation in the future on any scale was of: enormous imEortance. It was calculated that if the ydroge'' in a tablespoonful ?of water could b; transmuted into helium the energy liberated would be two hundred thousand kilowatt hours. Hence we* had in sight a source of energy far beyond the dreams of scientific fiction with which the human race coulii alter the olimat© of the earth on which it dwells, or, possibly,' migrate to a neighbouring planet. The possibility bad been discussed that this so-called atomic. energy, when liberated, would be out of our control/ In this case, Tt : all the .hydrogen on the earth was detonated into .helium, the earth and. all its inhabitants -.would be dissipated into space, and the successful experiment would be 'published throughout the whole' universe'as a' new star. One should hasten to assure the public that the probability of this catastrophe was practically . negligible. . //•.

"FIXED" NITROGEN..

Discussing the importance of nitrogen as the. basis of fertilisers and "of explosives for peaceful, -as well as belligerent purposes, the London Times explains that while more than ' threequarters of the volume of tho atmosphere consists of nitrogen, the gas enters,into chemical combination with other elements with a reluctance that can be overcome only by the utilisation of largo quantities of energy. Instead of speaking of "fixed" nitrogen, it would be as correct'and more intelligible to speak of energy fixed in compounds of nitrogen.- Until shortly before the war the world obtained its' fixed nitrogen almost entirely from natural beds in South' Auierica. But in a number of laboratories, notably by Crookes and Rayleigh- in England, Vnetfiods had been devised by which fixed . nitrogen could bo produced artificially, • starting either with the nitrogen bf the air or with relatively useless ijitrogen compounds, such as ammonia-r-a by-product of , the gas industry. The . next, stage, still in active progress,. was the transformation of laboratory experiments into practical manufacturing methods. Norway and Germany were the "first to accomplish this result on a' large scalie. Since thert other coUntriaa have 4 been following the lead. There are now nearly a dozen processes, each successful on a non-economic scale, and several -actually having reached, or rapidly approaching, an' economic scale. But, let it be repeated, "fixed" nitrogen is really ."fixed" energy. With the single etception bf'the Hausser process, in which the energy is obtained by explosion inside ti borpb,' all require an abundant supply of energy from some external source. The percentage of the energy expended which ' ts actually utored varies from about two (in the electric arc process where air i« forced to combine in an electric flame) to some forty or fifty. Doubtless great improvement will be made, as in other industries, in, the direction' of 1 more economical transformation. But when the raw material is energy', and the product stored energy. the future rests .with the country which obtains its energy most cheaply, by the employment of water-power, by the construction of generating stations on a huge, scale, and by a proper us© ■of 'Coal. 'Energy must bo made cheap if stored energy 'is 'to' tfe cheap. ,