Page:On the economy of machinery and manufactures - Babbage - 1846.djvu/281

Rh {| class="_ruled_cols" ! Injury arising from ! Fast Coach. ! Heavy Waggon.
 * Atmospheric changes || 20 || 20&puncsp;&numsp;
 * Wheels || 20 || 35.5
 * Horses' Feet drawing || 60 || 44.5
 * | Total Injury
 * | 100
 * | 100&puncsp;&numsp;
 * }
 * | Total Injury
 * | 100
 * | 100&puncsp;&numsp;
 * }

Supposing it, therefore, to be ascertained that the wheels of steam-carriages do no more injury to roads than other carriages of equal weight travelling with the same velocity, the committee now possessed the means of approximating to a just rate of toll for steam-carriages.

(302.) As connected with this subject, and as affording most valuable information upon points in which, previous to experiment, widely different opinions have been entertained; the following extract is inserted from Mr. Telford's Report on the State of the Holyhead and Liverpool Roads. The instrument employed for the comparison was invented by Mr. Macneill; and the road between London and Shrewsbury was selected for the place of experiment.

The general results, when a waggon weighing 21 cwt. was used on different sorts of roads, are as follows:—