A LETTER FROM GALLIA. 



TORSION IN FARM WAGONS, FARM MACHINERY,. 



AND GENERAL CARRIAGES (AS UNDERSTOOD 



IN FRANCE AND ENGLAND). POINTERS 



FOR AMERICAN FARM IMPLEMENT 



PEOPLE. [ILLUSTRATED] . 



BY L. LODIAN, C.E., PARIS, FRANCE. 



[Exclusively Contributed.] 



In conjunction with the eminent technician, M. Bannon-Roi, of "la 

 Herre*', Val-Roger, Villiers-sur-Marne, Paris, I have been able to com- 

 pile the following data, which it is considered will be useful to your 

 readers. 



Wagon-builders or implement-makers are often called upon to do 

 work entirely new to them in form or in action of parts, and to esti- 

 mate results which would puzzle a carriage-maker whose work if 

 really done in his shop at all is often a tame reiteration of patterns: 

 and methods, with conventional insipidity and inaccuracy. It is torsion 

 which makes a carriage of the same weight, with the wheels close to- 

 gether, when used over uneven roads. 



Centralized weight may be assumed to be marked "o" zero. Now 

 the supporting contact on the ground by wheels immediately under 

 trie body- weight, would make it freest from torsion on uneven ground. 

 Recentralize that weight by extending it many feet apart at four 

 'whee-lbearing'-points these to bear on a road of uneven surface, 

 and torsion is created in the body and carriage however rigid they 

 may be. Springs relieve the action on the body some forms of 

 springs more than others.; but the torsion is still manifest. Its action 

 is to press recurrently on one wheel, then the other, in involuntary 

 action, as most roads are hollows and hillocks in miniature. Should 

 the undulating action and re-action occur in this form, Fig. I., A, B, 

 C, the wheel in a hollow of the road at B, if the weight undulation 

 from one wheel to the other happened to undulate forcibly downward 

 as at B, the draft to surmount the hillock at G is increased by the tor- 

 sion causing greater wheel- pressure on the ground; and the further 

 the wheel from the center of the load, the greater the leverage thrown 

 on the far-away wheel. 



Here it maybe remarked that it is not the mere act of body- 

 twisting which augments the draft; for if it twisted as easy as a sheet 

 of paper, the draft would be correspondingly lighter for such an easy- 



