DREJUDICE, once established, can becomeastonish ingly strong and almost impossible to banish. Many
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years ago, almost in the early days of the application of the oil engine to road transport, it was, suggested, and believed, too, in many quarters, that the fumes from an oilengiried vehicle were poisonous, muck more so than those from a petrol-engined machine. In Particular, the view was held that food carried in oilers has likely to be contaminated,. whereas that in. petrol lorries Was immune from such a risk.
This challenge was promptly taken up by some friends of mine, who went to the trouble of engaging an independent and unbiased • authority, a firm . of consulting chemists and analysts, to investigate the matter. They did so, and their findings not merely exonerated the oil engine from blame in this respect, but actually showed that, of the two types,. the fumes from the petrol engine were the more harmful and that, indeed, those from the oil engine were innocuous.
: The results of that investigation were so positive and incontrovertible that I for,one deemed the question settled, never again to be raised. judge of my surprise, then, when, meeting a haulier friend of mine the other day, shortly after the first of the articles " Oil or Petrol for 30 m.p.h. Lorries1" had'appeared, he brought the sebject forward. once again.
" That was an interesting article of yours," he began, " on whether to buy oil or petrol-engined vehicles. I suppose, in the second instalment, you conclude the argunients by proving, that, economically, the oi: engine is the only possible choice? "
" Something, like that," I replied. " As a Matter of fact I have been of that opinion for some time."
" Humph;" was all I got by way of reply. You are a petrol' enthusiast,, aren't you? " I asked.
" By no means," he answered. " On the contrary, I would like to run oil-engined vehicles, but I daren't."
" You daren't," I exclaimed. " What on earth do you mean?
" Just this.' Most of my traffic is with food merchants, -and it would never do for me to turn upat their loading bays with an oil-engined lorry." .
" Why not? What harm can an oilengined vehicle do in that position? " "Oh, the exhaust gas contaminates the food."
" It does' nothingof thekind," I interjected.
" Well, at least it is worse than the exhaust from a petrol engine."
" It is nothing of the sort," I retorted, " in fact, the exhaust gas from an oil engine is not at all harmful to food."
Can,you prove that " he asked.
" Most certainly I can.,' I answered..
" Well do me a favour," he begged, " write an article in 'The' Commercial Motor' to prove it." " I can hardly do that," I protested. " I cannot write an article just to please one man. The Editor will only accept articles of general interest, those which will benefit the industry asa whole." •
." This is of general interest," he replied. ." I am not by any means the only one who is debarred {TOM using an oil-engined vehicle for carrying food; there is a • general prejudice against it. I know several of my customers— big food manufacturers and merchants who run their own, fleets as well awmploying hauliers—and none of them will have an oil-engmed Vehicle in the place."
" U that be the case," I said, ".I will submit an article to The Editor an stress the importance of the subject."' Since then., I have looked up my notes on the subject and they form the context of what follows.
These experiments, carried out before the war, were made comparative by the use of exhaust gases from (I) an oil engine using a standard heavy oil fuel; (2) a petrol engine using petrol containing lead tetraethyl ; (3) a petrol engine using ordinary commercial petrol. • In the course of the experiments, this consulting Chemist exposed to the exhaustfrom engines using these fuels samples of the foodstuffs enumerated below. The samples were contained in three large tin boxes, one set in each. In each experiment the exhaust gases were allowed to blow for half an hour directly into the boxes containing the foodstuffs, which were not wrapped or covered.
At the end of this tinie the lids were put on the boxes, which were then brought to the laboratory where they were .
opened and the foodstuffs smelt and tasted. Fruit, bread, sweets and milk were found to be slightIY affected in smell, but not at all in taste. Cream cakes were slightly tainted both in smell and taste, whilst margarine and bacon were more strongly affected.
It was agreed by all who smelt and tasted the samples that where they were tainted at all the effect produced by petrol exhaust was much more disagreeable than that produced by heavy-oil exhaust.
The lids were again put on the boxes, which were then left for three days. Upon opening them again, the smell of the exhaust gases was just discernible in the tetraethyl petrol exhaust and had practically disappeared in the others. The taint in the margarine and bacon, however, although materially lessened, could yet be detected (although it is, perhaps, questionable whether it would have been noticed had attention not been directed to it). , Samples of the exhaust gases were collected and analysed, with the following percentage results:— , oil-engine exhaust is less objectionable than from a petrol. engine exhaust.
A further test was then made with the oil-engined vehicle, one which more nearly reproduces (although it was much more severe) the conditions likely to occur in actual work, when vans are used for the conveyance and delivery of foodstuffs.
Samples of food—cream cakes, bread, biscuits, milk, meat and butter—were placed, on the back of a standing lorry with its engine running. The samples were Ideated at a point above the exhaust pipe,. so as to be in line with the ' rising fumes. A similar set of samples was placed about a foot away from the end of the exhaust pipe, although not in the direct line of the flow of gas. The samples remained exposed for an hour and at the end of this time node of them gave any indication of contamination.
The results are decisive enough to answer any question which may be raised as to the effea of an oil-engine exhaust on food, bearing in mind that, in normal circumstances, food conveyed on a vehicle is not subjected to contact with exhaust fumes to anything like the extent provided for in these experiments.
Attention should be directed, in particular, to the above chemical analysis of the exhaust gases, as they definitely establish the fact that exhaust fumes from oil engines are completely innocuous.
The danger which arises from the presence of carbon monoxide in the exhaust gas of a motor vehicle cannot he stressed too strongly Garages and premises used for the storage of vehicles are often not aaquately ventilated and in view of this the danger resulting from the running of a petrol engine in an enclosed space often arises.
The oil engine, with its absence of deleterious gases in the exhaust, completely removes this danger and, as a' result, in establishments where oil engines only are used, there should" be a diminution in the number of accidents which bccur from this cause, as well as an improVement in the general health of drivers and mechanics who spend a lot of
time in the vicinity of running engines. S.T.R.