428 SCIENCE OF AGRICULTURE. Part II 



Sect. VII. Machines of Deportation. 



2743. The carriage or conveyance machines of agriculture are chiefly carts and waggons, 

 and their several varieties. 



SuBSECT. 1. Carts. 



2744. Carts, like other implements, vary in their forms and modes of construction, 

 according to the nature and situation of the roads, and many other local circumstances ; 

 but, for the purposes of farming, those of the single-horse kind are in general the most 

 advantageous and useful. The advantages of single-horse carts. Lord R. Seymour 

 observes {Ann. Jg. xxvii.), are universally admitted, wherever they have been attentively 

 compared with carriages of any other description. A horse, when he acts singly, will do 

 half as much more work as when he acts in conjunction with another ; that is to say, 

 that two horses will, separately,, do as much work as three conjunctively ; this arises, in 

 the first place, from the single horse being so near the load he draws ; and, in the next 

 place, from the point or line of draught being so much below his breast, it being usual 

 to make the wheels of single-horse carts low. A horse harnessed singly has nothing but 

 his load to contend with ; whereas, when he draws in conjunction with another, he is 

 generally embarrassed by some difference of rate, the horse behind or before him moving 

 quicker or slower than himself; he is likewise frequently inconvenienced by the greater 

 or less height of his neighbour : these considerations give a decided advantage to the 

 single-horse cart. The very great ease with which a low cart is filled may be added ; as 

 a man may load it, with the help of a long-handled shovel or fork, by means of his hands 

 only ; whereas, in order to fill a higher cart, not only the man's back, but his arms and 

 whole person must be exerted. To the use of single horses in draught there can be no 

 objection, unless it be the supposed necessity of additional drivers created by it : the fact 

 however is, that it has no such effect; for horses once in the habit of going singly, will 

 follow each other as uniformly and as steadily as they do when harnessed together ; and 

 accordingly we see, on the most frequented roads in Ireland, men conducting three, four, 

 or five, single-horse carts each, without any inconvenience to the passengers ; such, 

 likewise, is the case where lime and coal are generally carried upon pack-horses. In 

 some of the northern counties of Biitain also, one man manages two or three, and 

 sometimes more, one-horse carts. 



2745. Carts drawn by one horse, or by two horses, says a writer whose authority is 

 unquestionable (Supp. Ency. Brit.), are the only farm carriages of some of the best 

 cultivated counties, and no other are ever used in Scotland. Their load depends upon 

 tlie strength of the horses, and nature of the roads ; but, in every case, it is asserted that 

 a given number of horses will draw a great deal more, according to some one third more, 

 in single-horse carts than in waggons. Two-horse carts are still the most common 

 among farmers in Scotland ; but those drawn by one horse, two of which are always 

 driven by one man, are unquestionably preferable for most purposes. The carriers of 

 the west of Scotland usually load from a ton to a ton and a half, on a single-horse cart, 

 and no where does it carry less than 1 2 cwt. if the roads are tolerable. 



2746. Wheels, such as are broad, with conical or convex rims, are common in England; 

 in Scotland the wheels are generally narrow, though broader ones are beginning to be 

 introduced. Those used for the common, or two-horse, carts, are usually about 4^ feet 

 high, and mounted on iron axles. The advantages of broad cylindrical wheels have been 

 illustrated with much force and ingenuity in several late publications. {Communications 

 to the Board of Agriculture, vol. ii. and vol. vii. part i.) 



2747. Large wheels to carts, drays, ^c. will, besides greatly increasing the facility of 

 draught, tend to lessen the number of accidents to which all two-wheeled carriages are 

 liable, from the shaft-horse falling down. To render this more evident, let us first 

 examine fg. 380., which is a rude sketch of a cart constructed in the usual manner, 



and supposed to be loaded with bricks, stone, sand, 

 or other heavy material. While thus loaded, and 

 the horse is in an erect position, the centre of 

 gravity (g) is almost directly over the axletree, in 

 which state the body of the cart is nearly balanced, 

 or only pressed upon the back of the horse with a 

 force equal to a few pounds' weight. But the horse 

 is supposed to have fallen : the consequence is, that 

 the centre of gravity is thrown much more forward ; the body of the cart and its load 

 becomes divided by the line a b, perpendicular to the axletree, into two very unequal 

 parts, c and d ; the whole of the increased portion (c) in front of the line acting as a 

 weight upon the horse, and only partly counterbalanced by the diminished portion (</) 

 behind the line. It frequently happens that this increased weight, so suddenly thrown 

 upon the shafts, snaps tliem short oft"; and, at all times, tends to prevent the horse from 

 rising until part of the load is removed. By adopting the larger wheels, and the bent 



