THE MOTORIST.

Northern Advocate, 23 August 1924, Page 11 (Supplement)

THE MOTORIST.

SPEED JUDGING. STANDARDS OF COMPARISON. Speed is very deceptive. From the policeman who honestly believes that one traversed the cross roads in the ten miles an hour H«Nt at over 30, to the owner of a Super-supersports model, who confidently asserts that his "bus ,, exceeded 70 miles per hour on the road, there is an infinite range of

individuals who are all more or less unable to estimate speed with any degree of accuracy. The deception may

be one of two kinds. Thus, in some

eases, the actual speed may far exceed what one would estimate it to be, while in other cases, a vehicle may be travelling at a much slower rate than one would really suppose. It all depends upon the standard by which the

mind makes its comparisons, and this in all probability is set by the vehicle to which the individual is most a ecustomed. As regards the independent , observer on the highway, who sees a ear approaching, psychology, no doubt, plays an important part in the speed

estimate. If the- vehicle under observation is a rakish-looking sports model, with speedy lines, the occupants of which are muffled in flying helmets, j leather coats, and goggles, our pedes- | trian friend will be prepared to credit it with any speed which lie thinks high enough to meet the occasion.

Alternately, a steady-looking touring car, occupied by a family man in a bowler hat, will be allowed to prfss fit 40 miles per hour or so without adverse comment. We are more oenceraecl, however, with those who occupy the vehicle, and here it is that a number of small points play an important part in our estimate of the speed. The degree of protection afforded by the coach work is, no doubt, of great importance, likevriso the efficiency of the suspension system. Thus one may travel in a luxurious saloon body, mounted on a Rolls-Royce chassis at really dangerous speeds without knowing it, ow i ng to the lack of sensation produced.

The same velocity in a open sports car, with inadequate wind-screen, bucket seats, and low body sides! would appeal to one as a highly risky proceeding. Of course a standard example is found in the express train, which is so steady on the rails that the completely enclosed passengers can be carried along at GO miles per hour or more with very little sensation of speed, and no feeling of fear.

It may be of interest to point out (states the English Motor) that the nearness of surrounding objects influences estimation of speed. In a London tube, for example, the sides of the tunnel are so close to the carriage windows that they appear to hurtle past the passengers, giving the impression of an extremely high velocity. In reality, there are few "tubes' , on which a speed of 17 miles an hour is exceeded. There is no doubt that, on the road, acceleration plays a prominent part in speed estimates. For instance, if a man is familiar with a steady-going overloaded touring ear, and then takes n run in a "sports" capable of accelerating to 40 miles per hour in a mattor of seconds, on attaining this speed he will be apt to imagine that a far higher pace has been reached. In other words, one can slowly attain a high speed without much sensation, and without anything like the exliilnrating effect of the sudden leap onward from a walking pace. tire. some simple remedies. Of all the ills the motorist is heir to there is none so devastating in its possible effects and none which fills us with such a feeling of appalling helplessness as a fire, yet few of us trouble In carry an extinguisher, writes C.'A.P. in the "Light Car and the Cycle C;il". This is probably because it is .-i catastrophe which rarely overtakes us, yet it must not be supposed that it is outside the bounds of possibility. Tt may happen to the most careful driver fit any moment, and a few hints on how to deal with it mav not be amis*.

First, as to the causes which may bring it about. A broken petrol pipe < or a lealciny carburetter, if in close contact with a hot exhaust pipe, is a possible cause. A blowbaek into the carburetter, owing to deranged ignition timing, or a sticiting inlet valvet, may cause a conflagration, and, although sue]) mishaps are less common than they were in the days of automatic valves, they have been Icnown to happen, and will, doubtless happen a.Eraiti. ■fixeesive flooding of the carburetter when the engine is cold is also a d.inuer, aiul a utrangler should be used in preference. As a matter of fact, fires are more liable to start in Mie neighbourhood of the carbure^j^^m^^^^^^|^^M|^ii|

In case of lire the first thing to do is to turn off the petrol tap, the next to speed the engine up. It is a great mistake to stop it, as the iire feeds on the petrol in the float chamber, and the sooner this can be exhausted the better.

It is for this reason that a petrol tap on the driver's side of the dash is preferable to one under the bonnet, ns in the latter case an outbreak of fire may make it impossible to reach the tap.

The most successful form of extinguishers for use with petrol fires are those in which a liquid such as car-bon-tetra-chloride (C.T.C.) is used. This has the property of turning into an expert and heavy gas which blankets the flames by excluding the air, without which petrol cannot burn.

Never attempt to extinguish a petrol fire by pouring water on it. This only has the effect of spreading the trouble and is highly dangerous. If possible .sand or soil should be used. The

writer on one occasion succeeded in smothering a A r cry promising fire with an armful or damp grass, which by a fortunate coincidence happened to be lying by the roadside.