Are formed of wrought Iron, and are the chief support of
The Carriage[11].
Four Wheeled Carriages are divided into two parts, the Upper and Under Carriage.
The Upper is the main one, on which the Body is hung.
The Under Carriage is the conductor, and is turned by means of the Pole which acts on a centre-pin, called the Perch Bolt, which goes through the fore Axle-tree bed and fore transom, and secures the fore or under Carriage to the Upper one.
The Hind Wheels are placed on the Upper, the Fore Wheels on the Under Carriage.
The utmost care should be taken to have every part made of good Town made Iron Work well wrought, and sound Wood well seasoned, and of sufficient strength, rather going to the extreme in thickness, than risking the lives of the Passengers by the oversetting of the Carriage, which often happens when an Axle-tree or a Perch, &c. breaks.
The Common Axle-tree is that which is in general use, it being much the cheapest, a pair of the best case hardened costing only £9. 9s.
Collinge’s Axles have many advantages, which more than compensate the higher first charge for them, which is £28. 7s., but they wear so much longer, and the silent and steady motion they preserve to the Wheels, and the convenience of retaining Oil enough to travel a Journey of 30 Miles a day for 9 Months, that is, above 7,500 Miles, (i. e. if the Carriage does travel every day) without replenishing with Oil: the Common Axle will hardly travel 100 Miles without requiring the Wheels to be taken off and greased.
In the ordinary Town Work—say, on an average, about 10 Miles a day, Oiling twice a Year is enough: Mr. Collinge sends a person to do this, and charges 2s. for each Wheel; if a new Leather Washer is wanted, 1s. 6d. is charged for each: these are rarely required oftener than once in nine months.