ON DRAUGHT. 



The investigation of the subject of draught by animal power, to which this 

 treatise is devoted, and which will form an appropriate supplement to an 

 account of the Horse, — has frequently occupied the attention of theoretical 

 and practical men ; so much so, that our object will be to collect what has 

 been said and done, and, by arranging it methodically, to show in what manner 

 the information may be applied and rendered useful, rather than to attempt to 

 produce anything absolutely new upon the subject. Notwithstanding, however, 

 all that has been written, if we open any of the authors who have treated the 

 subject, in the hope of obtaining direct practical information, we shall be much 

 disappointed. 



It might have been expected that the particular result of every method 

 known and in use for the conveyance of a load from one spot to another, by 

 animal power, whether by sledges, by wheel-carriages, or by water, as in canals, 

 being so constantly and necessarily a matter of practical' experiment, would 

 have been accurately known and recorded ;- — but the contrary is too much 

 the case. 



The theoretical investigations have been made with too little reference to 

 what really takes place in practice ; jand the practical portion of the subject 

 has not generally been treated in that useful and comprehensive manner which 

 it deserves and demands. 



In fact, there is hardly a question in practical mechanics on which, though 

 much has been written, opinions are apparently less fixed ; or on which the 

 information we do possess is in a less defined and available state. 



One great object of research has been the average force of traction or power 

 of the horse. 



If we consult the most approved authors and experimentalists, Desaguilliers, 

 Smeaton, &c, we find this power variously stated as equal to 801hs., lOOlbs., 

 1501bs., and even 2001bs. : we arc therefore left almost as ignorant as before ; 

 but the knowledge of this average power is fortunately of little importance in 

 practice. It is the knowledge of the best application,, and of the effect, of that 

 power which alone is useful: and these are governed by circumstances so 

 varying and dissimilar, such as the form and state of the road, the structure 

 of the carriage, the size and friction of the wheels, &c., &c. ; that scarcely any 

 two cases of draught would, as regards the effect of the power of the horse, 

 present the same results. 



The difference of opinion here manifest is still greater when existing on a 

 purely practical question. 



In the inquiries instituted by a committee of the House of Commons in 

 180G and 1808, on the subject of roads and carriages, two well-informed prac- 

 tical men, Mr. Russell of Exeter and Mr. Deacon of Islington, the most 

 extensive carriers in England, were examined upon an important question viz., 

 the advantage or disadvantage of a particular form of wheel. It was stated 

 by one that, having given the wheels in question a twelve months' trial, he 

 found that they tended to injure the road and increase the draught in the pro- 

 portion of four to five; while it was stated by the other, who had also made tha 



