Page:The Working and Management of an English Railway.djvu/166

 fact that the heat, before it has altogether disappeared, can be restored by merely shaking the receptacle, and that the heat is retained nearly three times as long as in the ordinary hot-water tins, viz., for about 8 hours, thus avoiding the inconvenience and annoyance to passengers of continually changing the foot-warmers on a long night journey. The acetate of soda used for this purpose should possess a slightly alkaline re-action to litmus test paper, and should be commercially free from sulphate-chloride and carbonate of sodium, as well as from acetate of lime. It should not possess any unpleasant odour of tarry matter, and its total impurities should not exceed 2 per cent. The warmers are charged in the following manner:— The acetate of soda is first placed in a large iron tank and reduced by heat to a liquid, of which seven quarts are placed in each warmer. Seven ounces of water are added, and two cast iron balls, each two inches in diameter, and weighing 20 ounces, are placed inside. The aperture at the end, through which the liquid has been introduced, is now covered by a cap, soldered down, with a small hole left in the centre. The warmer is placed in another tank, and the contents again brought to boiling point, when the receptacle is hermetically sealed, and is then ready for use.

The sleeping saloons in the through trains between London and Scotland, Holyhead, Liverpool, and Manchester, are warmed by means of high-pressure hot-water pipes, each saloon being supplied with a small heating apparatus for the purpose.

The Lighting of Carriages.—Until recent years the carriages upon the London and North-Western Railway were all lighted by means of oil-lamps, but this