204 Description of the Neiccastle Dynanometer. 



by the light of Flemish experience, with a view to their gradual 

 removal. 



Under any circumstances, it is highly satisfactory to find that 

 mutual confidence can subsist in England between the buyers 

 and sellers of flax-straw, under which j)rices are realised by the 

 grower, which, if they do not realise our highest aspirations, are 

 at present undoubtedly remunerative. 



XVIII. — A Description of the Neiccastle Dynamometer. 

 By C. E. Amos. 



The annexed engraving represents a photographic view of the 

 Newcastle Dynamometer, used for testing the force required to 

 work the steam-plough exhibited at the Newcastle Meeting of 

 this Society. 



On page 409, Part II., \'()1. xxv., tlie necessity for an instru- 

 ment of the kind is shown, and the following description is there 

 given. "The instrument consists of a strong wooden frame 

 mounted upon carriage-wheels, having on its centre a strong 

 vertical cast-iron socket. A cast-iron screw column, fitted with 

 a fly-nut, drops into this socket, and moves freely in it, and the 

 column can be raised or lowered by the fly-nut. To the top of 

 the column is fitted a long arm of wood, by a joint at the centre, 

 so that either end can be raised or depressed. The arm thus 

 possesses a movement both horizontal and vertical, like that of a 

 transit instrument. At each extremity of the arm a pulley is 

 placed, which turns freely on vertical pins, the centres of these 

 pulleys being 18 feet apart. At the centre of the arm is a cen- 

 tral pulley Avith a vertical spindle, carried by two strong springs. 

 These springs are so placed that they deflect the central pulley 

 12 inches out of a straight line Ijctween the other two. The 

 rope passes over the end ])ulleys and under the central one, so 

 that the deflexitni of the unloaded rope is 12 inches. The instru- 

 ment being fixed in a position between the engine and the 

 cultivator, the tractive force on the rope is shown by the deflexion 

 of the middle pullev becoming less. The greater the tractive 

 force the less the deflexion of the rope." 



I will endeavour to explain the construction and principle of 

 action of this machine somewhat in detail by the aid of the 

 following diagrams : — 



In diagram Fig. 2, A and B represent two pulleys placed 18 

 feet apart. M is also a pulley placed between them, the distance 

 My being 12 inches. P is a standaid carrving a strong spring, 

 S, the extreme end of which carries the pullev M. 



The 



