In the United States, the industry began under great difficulties. The roads, except in the immediate outskirts of the larger cities, were abominable, and no system of suspension that could make them tolerable had yet been discovered. But though starting late, by 1906 the United States overtook and passed France, becoming the foremost car building and car using nation of the world. Nowhere else are factories worked upon so large a scale, and nowhere else are really serviceable cars so light and so cheap. And the greatest recent improvement in the gasolene engine, the Knight sleeve-valve, is an American invention. It is, altogether, a curious story, this struggle in which England, Germany and France, one after another, seemed destined to attain the leadership which in the end fell to the United States.
Turning to the subsidiary articles which relate to motoring, the gasolene engine is elaborately discussed in Oil Engine (Vol. 20, p. 35), by Dugald Clerk, an expert engineer and himself the inventor of the Clerk cycle engine. This article shows how complete a change in engineering practice was effected in 1883, when it was demonstrated that small engines could be run at a thousand revolutions a minute, a speed four times as great as any previously contemplated. All the types of carburetter are described, with mechanical diagrams. Other diagrams show the action of the inner and outer sleeves of the Knight valves. Gasolene, and the experiments made in search of a less costly fuel, are dealt with in the article Fuel (Vol. 11, p. 274), by Prof. Georg Lunge, of the Zurich Polytechnic, the greatest of all authorities on the subject. Tires, the bugbear of every car-owner, form the subject of a separate article Tire (Vol. 26, p. 1006), by Archibald Sharp, which contains a number of curious and instructive diagrams showing the direction of the stress on a tire at the point where the road slightly flattens it. Rubber (Vol. 23, p. 795), by W. R. Dunstan, president of the International Association of Tropical Agriculture, is well worth reading for its information as to the effect upon tires of exposure to air and light, apart from wear. The materials used, and the mechanical principles involved, in the construction of cars are discussed in a number of separate articles under obvious titles.
PHOTOGRAPHY
A large place, in any review of recreations, must be given to photography, which, even in its most elementary form, provides a record and an echo of an infinite variety of amusements, and, after a little study, not only does this all the better, but becomes a delightful art in itself, to be enjoyed in-doors as well as out-doors, at all hours and at all seasons. The amateur can find no more authoritative, full and yet concise manual of the subject than the Britannica article Photography (Vol. 21, p. 485), equivalent to about 125 pages of this Guide. The first section on History and Technique is by Sir William de Wiveleslie Abney, author of Instruction in Photography, Colour Vision, etc. Next is a section on photographic apparatus by Major-Gen. James Waterhouse, whose photographic work in India is known throughout the world. And then comes a discussion of pictorial photography by A. Horsley Hinton, author of Practical Pictorial Photography. The following is an outline of the article:
History.—Eighteenth century experiments of Scheele, Senebier and Count Rumford. Early 19th century discoveries. The Daguerreotype and its improvements by Goddard, Claudet and Fizeau. The Fox-Talbot process. Albumen process on glass. Collodion process. Positive pictures by the collodion process. Moist collodion process. Dry-plates; alkaline developers with formulae for some of the most effective; developers of organic salts of iron; developer restrainers. Dry-plate bath process of R. Manners Gordon, with formula for preservative. Collodion emulsion processes—work of Bolton and Sayce and of M. C. Lea and W. Cooper; Bolton’s modification; Col. Wortley introduces strongly alkaline developer. Formula for alkaline developer for collodion plates. Gelatin emulsion process—Maddox (1871), King (1873), Burgess (1873), Stas (1874), Bennett (1878), Abney (1879), van Monckhoven (1879) and his use of hydrobromic acid on silver carbonate with ammonia. Heating the emulsion—Wortley (1879), Mansfield (1879).
Relative rapidities of the processes described.
| Daguerreotype, originally, | Half an hour’s | exposure. |
| Calotype | 2 or 3 minutes’ | „ |
| Collodion | 10 seconds’ | „ |
| Collodion emulsion | 15 seconds’ | „ |
| Rapid gelatin emulsion | ¹⁄₁₅ second | „ |
The second part of the article deals with the technique of photography. The major topics in it are:
Gelatin emulsions: formulae and directions for emulsion with and without ammonia. Coating the plates. Exposure. Development, with formula for alkaline developer. Intensifying and varnishing the negative.
Printing processes. Albumen method of Fox-Talbot. Sensitizing bath. Toning and fixing the print—formulae for toning-bath. Collodio-chloride silver printing process: Simpson’s formula. Gelatino-citrochloride emulsion: Abney’s formula. Printing with uranium salts: an early formula. Self-toning papers. Printing with chromates: carbon prints—work of Ponton, Becquerel, Dixon, Fox-Talbot, Poitevin, Pouncey, Fargier, Swan, Johnson and Sawyer. Printing with salts of iron. Photo-mechanical printing processes: discoveries of Oreloth, de Motay, Marechal and Albert; “Lichtdruck” and heliotype. Woodbury type. Photolithography: the work of E. J. Asser, J. W. Osborne and Sir H. James.