The Combustion of Hydrocarbons.
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Professor Bone, of Leeds University, in a paper delivered at the Institution of Mechanical Engineers on Wednesday last week, at the opening meeting of the ensuing session of the Institute of Automobile Engineers, adduced very interesting evidence in support of the modern theory that hydrogen is not preferentially burnt in the cylinder of an explosion motor. He entertained a large audience with particulars of numerous important experiments, which have been conducted during the past six years, in support of his own contention that intermediate oxygenated compounds are formed by the addition of oxygen to the hydrocarbon molecules, to the exclusion of any selective combustion either of the carbon or hydrogen constituents. These products of an intermediate stage of combustion, of which formaldehyde and acetaldehyde are examples, whilst capable of isolation where combustion is deliberately retarded by temperature reduction, are not to be detected by any ordinary gas analyses taken under working conditions. Professor Bone advanced the belief that such compounds rapidly dissociate into carbon monoxide and hydrogen, which are subsequently completely burnt to carbon dioxide and steam; but, owing to the almost inconceivable rapidity with which the explosion wave is propagated throughout the mixture, these stages defy separation in the course of the impulse stroke in an internals combustion engine. Professor Bone delighted his hearers with particulars showing how the velocity of combustion varies according to the presence of inert gases, or even an excess of oxygen, by as much as 5o per cent., and many of those who were present will have learnt, for the first time, that such velocities are as high, for ideal mixtures, as it mile per second. After pointing to the work of Dalton.
Dixon, Baker, and Smithells, he gave the various reasons for to-day's acceptance by chemists of the view that carbon always burns to carbon monoxide in the first instance, and then to carbon dioxide, and remarked how hard the belief died that carbon monoxide was formed by the reduction of the dioxide in the presence of an excess of carbon. This was an exploded fallacy.
The practical bearings of Professor Bone's paper on roadmotor questions are these : (a) unsaturated hydrocarbons, which contain an unusually large proportion of carbon, such as those from the Borneo and other' Eastern fields, can, quae perfect combustion, be used without fear of sooty deposit, provided the necessary additional air is admitted to the cylinders; and (b) any shortage of air will result in a relatively high percentage yield of carbon monoxide and hydrogen, and not in, as has been generally supposed, a tine deposit or discharge of unburnt carbon'. His investigations have admirably supplemented those of Professor Dixon, as recorded in the proceedings of the Royal Society for the year 1893, and are worthy of his own exhaustive experiments which are to be found, from the year 1902 forward, in the proceedings of the Chemical Society.
Highways in Relation to Side-slip.
We are pleased to observe that our contemporary, "The Surveyor," which is the official organ of the Society of Municipal and County Engineers, has given its cordial approval and support to our suggestion, that the Society of .Motor Manufacturers and Traders should invite the Surveyors and Engineers of London Borough Councils to .meet in conference, in order to discuss the important outstanding difficulties in connection with road construction, repair, cleansing, and maintenance in relation to motor traffic, and, more particularly, in their bearing upon the growth of motorbus traffic. Operating companies and their engineers are rightly grumbling at the vile condition in which our street surfaces are so often found, but it most not be overlooked that there are, as in every mundane case, two sides to the question. Borough officials are by no means their own masters : they are subject to the dictates of their committees, and the limitations of the funds placed at their disposal by finance committees. Further, in all matters appertaining to highway construction, they are disinclined to accept ally innovations, or to follow any departures from accepted and proved standards of cross-section or maintenance, without very good cause. We believe, now that the initial step has been taken to bring about this closer touch, in regard to the important subjects named above, between the responsible officers of London Boroughs and dele!'sates of the manufacturing and operating interests to which " Tint COMMERCIAL MOTOR "is devoted, that real benefits for the public at large will accrue. We see no reason why a free interchange of opinions, at a series of in camera meetings to be held during the next few months, should not enable some authoritative pronouncement to be made, as it properly might, in the course of one of the papers to be presented before the Conference of Engineers and Surveyors, in connection with their own section of the Building Trades Exhibition, at Olympia, in April of next year.
Cardiff's Municipal Motors.
Various reports have appeared in the Press, during the last nine months, in reference to the disappointing results that have been obtained with four steam wagons at Cardiff. Arising from these notices, the most gloomy views were advanced, at Salford, in June of this year, as to the prospects of mechanical power in any application to dust or ref we collection, and it is now generalh agreed that the long periods of enforced idleness operate most adversely on the motor's potential capacity for effecting a saving in haulage and conveyance charges. An interview with Mr. W. Harpur, the City Engineer of Cardiff, will be found elsewhere in this issue, and we hope to be able to record, before the end of 1907, that a solution of his present difficulties has been reached, and that the existing loss of, approximately, 5id. per ton of refuse, etc., collected and tipped has been converted to a small if not an equal gain from the cost standpoint. When the first two machines were ordered from Mann's Patent Steam Cart and Wagon Company, Limited, of Leeds, the late out-door superintendent at Cardiff was, to our knowledge, most strongly urged to work them in parallel, so that the tillers' time might not be wasted in travelling, as mere passengers, to and from the tips. This course has not, for good reasons no doubt, been adopted, and we are assured that such a plan of working is well-nigh impossible there.; but we must point out to other authorities which are studying the question, that Cardiff's difficulties should not be accepted as of universal application. It is not everywhere that at least four fillers per motor will be required to spend three hours per day per man in disposing of total loads amounting to 30 cubit: yards (or less) of refuse, even allowing that their meals are eaten at the tipping ground, yet this procedure has, so far, been good enough for Cardiff. Further, we are unable to follow why motor tillers are paid Is. 6d. per week more than those who are attached to the horse-drawn wagons. Since our visit to Cardiff, we have endeavoured to unravel this apparent inconsistency. Mr. Harpur believes that the motor fillers deserve increased pay, because, he writes, they " work more quickly." But, as he, at the same time, informs us that each horsed wagon does five trips per day, with a 2i-yard capacity, the greater amount of work would appear to be done by their fillers. In no event, on the statistics furnished, do the motor fillers handle as great a weight per man as do the horsewagon fillers, and we much fear that the motors' chances are hampered by the activities of a pro-labour council !
Mr. Harpur has told us that each horsed cart, with one filler in addition to the driver, and after making due provision for depreciation and maintenance, costs tas. 2d. per day, and that the cost per ton of refuse collected and tipped is is. .8.81d. : each wagon, therefore, averages 8.17 tons per day, or, say, 33ewt. per load. This exceptional result must be attributed to the level nature of the streets in Cardiff, and the same high performance is impossible as a rule. Turning to the motor costs, Mr. IIarpur has now got them down to 25. 2.25d. per ton, on a three-trip basis, which allows each motor to run a total of only about 18 miles per day, inclusive of journeys to and from work, morning and evening. The joint capacity of each motor and its two trailers, which are interchangeable for horse haulage and,
therefore, of the same height for loading, is to cubic yards, or, on the day's work accomplished, a total of 30 cubic yards. As Mr. [harper has reported that each motor, with its fillers and driver (who does no loading), and inclusive of maintenance, costs .„-C2 95_ per day, it is interesting to note that only 22.4 tons of refuse are dealt with, daily, per motor. Though possessed of four times the cubic capacity, each motor unit is only sufficiently turned to account to do 2.74 times the effective work of a horsed wagon, and this fact is, alone, more than enough to account for the 21 per cent, lesser cost of horsed wagons at Cardiff. As, however, the motors were purchased out of funds provided for current expenditure in the Health Department's work, and not with borrowed money, it is necessary, in order to allow any comparison elsewhere, to add, at a liberal estimate, four shillings per day for the depreciation of each. Even then, the present loss, notwithstanding the inefficient manner in which these motors are still being employed, is only 26 per cent. This difference, too, may be accepted, (pure conditions, as the maximum, between horses at their best and motors at their worst.
If the City Engineer of Cardiff wilt give fresh attention to this branch of his department's work, as soon as the bustle connected with the transfer of his offices to the new Town Hall is over, we are satisfied that, quite apart from the hopes he entertains of finding useful occupation for the wagons in other directions, he will be able to organise the dust and refuse collection so that more titan 26 per cent, of the existing cost per ton will be saved. Side-tipping wagons, as now in use at Merthyr Tydvil, would avoid the necessity for uncoupling and horsing at the tip, but Cardiff will be obliged, for the present at any rate, to turn its available plant to account. The methods now in vogue are open to improvement and better organisation. Parallel collection should not be rejected without further consideration, as the working of wagons in pairs enables the fillers to concentrate on one while the other is travelling to and from the tip. This system, in a modified form, has been adopted for the horsed wagons, as only the driver proceeds to the tip, while the tiller goes to another wagon. Failing a fundamental change of this character, Mr. Harpur's proposals to use the motors exclusively to haul several wagons at a time, to and from the tips, after their loading has been completed behind horses, should prove both effective and free from the nuisances which attach to a similar method of working by traction engine and a longer train of trucks_ Either re-arrangement would free the motors from what we are obliged to stigmatise as unequal labour charges, and the present incidence of which prejudices these vehicles most seriously, whilst it would introduce the element of flexibility which is now lacking. No doubt, too, Mr. Harpur and other municipal officers will give heed to the excellent suggestion from Mr. Harvey, the Borough Engineer of Merthyr Tydvil, to which we refer on page 210.
In conclusion, we feel that it is due to the manufacturers of the Cardiff wagons, Messrs. Mann, to direct attention to Mr. Harpur's high opinion of their qualities, and to emphasise the fact that their present failure to save money at Cardiff arises from no faults or defects in the machines themselves, but from the causes we have explained.