at the Norwich Meeting, 1849. 



555 



quired to produce 1 146 revolutions^ a rate of speed 62 per cent, 

 above his estimate. 



Table A gives various particulars respecting the machines tried 

 with the dynamometer. These for the most part require no 

 remark ; but column 9, which gives the draught in stones when 

 the machines were running empty, is well worthy of notice from 

 the great variation in the amount of power required. In one 

 instance it amounted to 48 st. It should be mentioned that this 

 was a six-horse machine, but after making all due allowance on 

 this score its draught when doing no work was far too great. 

 In another instance it will be observed that the draught was 

 44 St. To assist in forming an opinion respecting the figures 

 in this column it may be mentioned that the average draught of 

 a plough turning a furrow 9 inches by 6 rarely exceeds 24 stone, 

 and on light land (when not too dry) is generally under 20 

 stone. Yet this is considered a fair amount of work for a pair 

 of horses, and taking 10 to 12 stone as the average draught of 

 each horse, it appears that in no less than four of the machines 

 tried on this occasion^ and which professed to be four-horse 

 machines, it required the ordinary pull of three horses at plough 

 to drive them at their proper speed when doing no work. Had 

 these machines acquitted themselves ill when put to work, the 

 fact would scarcely have been worth notice, but it becomes im- 

 portant when we find that they were subsequently proved to be 

 some of the best exhibited. The result then of this first trial was 

 to show that the best threshing-machines now manufactured are 

 still far from perfect, and as the trials proceeded some progress 

 was made in detecting their weak points. 



It will have been gathered from the preceding remarks that 

 Table A gives the result of the application of an entirely new test 

 to threshing-machines, one, viz., which registers the amount of 

 force required to drive the machines when empty. Table B 

 records a further attempt to ascertain the proportions in which 

 the amount of draught given in column 9 of Table A should be 

 apportioned between the horse-works and the barn-works of the 

 respective machines. It will be observed that the number of the 



Table B. 



Stand, 



64 

 107 

 36 

 SI 

 44 



Art. 



Name. 



Hensman 

 Hurwood 

 Holmes . 

 Garrett . 

 Woods. • 



Horse 



of whole 

 iMachine. 



2-39 

 1*99 

 4-02 



Friction Friction 

 of Barn of Horse 

 Works. Works. 



1'38 

 •69 

 •97 



2-07 

 •46 



1-01 

 1-30 

 3-05 

 •71 

 2-35 



