ON DliAUGHT, 



The investigation of the subject of draught by animal power, to wliicli 

 this treatise is devoted, and which w^ill form an appropriate supplement to 

 an account of the Horse, has frequently occupied the attention of theo- 

 retical 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 expe- 

 riment, would have been accurately known and recorded ; but the contrary 

 is too much the case. 



The theoretical investigations have been made with too httle reference 

 to what really takes place in practice ; and 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. 



K we consult the most approved authors and experimentalists, Desaguil- 

 liers, Smeaton, &c., we find this power variously stated as equal to 80 lbs., 

 100 lbs., 150 lbs., and even 200 lbs.; we are therefore left almost as ignorant 

 as before ; but the knowledge of this average power is fortunately of 

 httle importance in practice. It is the knowledge of the best appHcation, 

 and of the efiect, 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 efiect of the power of the horse, present the same results. 



The difierence of opinion here manifest is still greater when existing on 

 a purely practical question. 



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

 1806 and 1808, on the subject of roads and carriages, two well-informed 

 practical 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 and disadvantage of a particular foi-ni 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 



