Twentieth Century Inventions: A Forecast

by George Sutherland

The explosive type of engine was next called into requisition to do battle against the living competitor of the engineer's handiwork. Petroleum and alcohol, when volatilised and mixed with air in due proportion, form explosive mixtures which are much more nearly instantaneous in their action than an elastic vapour like steam held under pressure in a boiler, and liberated to perform its work by comparatively slow expansion. The petroleum engine, as applied to the automobile, does its work in a series of jerks which provide for the unequal degrees of power required to cope with the unevenness of a road.

As against this, however, there are certain grave defects, due mainly to the use of highly inflammable oils vapourised at high temperatures; and these have impressed a large proportion of engineers with a belief that, in the long run, either electricity or steam will win the day. Storage batteries are well adapted for meeting the exigencies of the road, just as they are for those of tramway traffic, because, as soon as an extra strain is to be met, there is always the resource of coupling up fresh batteries held in reserve—a process which amounts to the same as yoking new horses to the vehicle in order to take it up a hill. In practice, however, it is found that the jerky vibratory motion of the gasoline automobile provides for this in a way almost as convenient, although not so pleasant.

The chance of the steam-engine being largely adopted for automobile work and for road traffic generally depends principally on the prospects of inventing a form of cylinder—or its equivalent—which will enable the driver to couple up fresh effective working parts of his machinery at will, just as may be done with storage batteries. A new form of steam cylinder designed to provide for this need will outwardly resemble a long pipe—one being fixed on each lower side of the vehicle—but inwardly it will be divided into compartments each of which will have its own separate piston. Practically there will thus be a series of cylinders having one piston-rod running through them all, but each having its own piston.

Normally, this machine will run with an admission of steam to only one or two of the cylinders; but when extra work has to be done the other cylinders will be called into requisition by the opening of the steam valves leading to them. Provision can be made for the automatic working of this adjustment by the introduction of a spring upon the piston-rod, so arranged that, as soon as the resistance reaches a certain point, a lever is actuated which opens the valves to admit steam to the reserve cylinders of the engine. On such occasions, of course, the consumption of steam must necessarily be greatly increased; but on the other hand the automatic system of the admission to each cylinder also results in a shutting off of the steam when little or no work is required. In fact, with a fully automatic action, regulating the consumption of steam exactly according to the amount of force necessary to drive the automobile, it would be possible to work even a single cylinder to much greater advantage than is done by the machines generally in use.

So heavy are the storage batteries needed for electric traction of the road motor-car that practically it is not found convenient to carry enough of cells to last for more than a twenty-mile run. The batteries must then either be replaced, or a delay of some three hours must occur while they are being recharged. The idea of establishing charging stations at almost every conceivable terminus of a run is quite chimerical; and, even if hundreds of such stations were provided for the convenience of the users of electric traction, the limitation imposed by being forced to follow the established routes would always give to the non-electric motor an advantage over its competitor.

The best hope for the storage battery on the automobile rests upon its convenience as a repository of reserve power in conjunction with such a prime motor as the steam-engine. A turbine worked by a jet of steam, as already described, and moving in a magnetic field to generate electricity for storage in a few cells, is a convenient form in which steam and electricity can be yoked together in order to secure a power of just the type suitable for driving an automobile. In the machine indicated the supply of the motive power is direct from the storage batteries, which can be coupled up in any required number according to the exigencies of the road. Automatic gear may be introduced by an adaptation of the principle already referred to.

In a light road-motor for carrying one or two persons on holiday trips or business rounds, the quality of adaptability of the source of power to the sudden demands due to differences of level in the road is not so absolutely essential as it is in traction engines designed for the transport of goods over ordinary roads. In the former class of work the waste of power involved in employing a motor of strength sufficient to climb hills—although the bulk of the distance to be travelled is along level roads—may not be at all so serious as to overbalance the many and manifest advantages of the automobile principle. At the same time, as has already been indicated, there is no doubt whatever that when proper automatic shut-off contrivances have been applied for economising mechanical energy in the passenger road-motor, an immense impetus will be given to its advancement.

In the road traction-engine the need for what may be termed effort on the part of the mechanism is much greater, more especially as the competition against horse-traction is conducted on terms so much more nearly level. A team of strong draught-horses driven by one man on a well-loaded waggon is a far more economical installation of power than a two-horse buggy carrying one or two passengers.

The asphalt and macadamised tracks which are now being laid down along the sides of roads for the convenience of cyclists, are the significant forerunners of an improvement destined to produce a revolution in road traffic during the twentieth century. When automobiles have become very much more numerous, and local authorities find that the settlement of wealthy or comparatively well-to-do families in their neighbourhoods may depend very largely upon the question whether light road-motor traffic may be conveniently conducted to and from the nearest city, an immense impetus will be administered to the reasonable efforts made for catering for the demand for tracks for the accommodation of automobiles, both private and public.

The tyranny of the railway station will then be to a large extent mitigated, and suburban or country residents will no longer be practically compelled to crowd up close to each station on their lines of railroad. Under existing conditions many of those who travel fifteen or twenty miles to business every day live just as close to one another, and with nearly as marked a lack of space for lawn and garden, as if they lived within the city. The bunchy nature of settlement promoted by railways must have excited the notice of any intelligent observer during the past twenty or thirty years—that is to say since the suburban railroad began to take its place as an important factor in determining the locating of population.