42 POWER AND THE PLOW 



wide, which took the place of the drive- wheels. Steam was 

 supplied by an upright tubular boiler, with 300 feet of heating 

 surface. The driving drum was bulged in the middle like a 

 barrel to permit of easy turning, the modern compensating gear 

 not having been invented. This engine drew eight plows 

 at the rate of three miles per hour over original prairie 

 sod, hence steam plowing on a large scale is by no means 

 a modern idea. Several other men in Connecticut, 

 New York, and New Jersey were at the same time busy 

 on traction engines for plowing, In 1871 the Royal Agri- 

 cultural Society of England held trials extending over 

 several months, in which the adaptability of all plowing 

 and cultivating engines up to that time were thoroughly 

 tested. Steam had been applied to the plow through 

 cables by John Fowler & Sons, of Leeds, in much the same 

 manner as their outfits are built to-day, and their 

 tackle won high honors. In the meantime, the steam 

 carriage as a factor in road transportation seems to have 

 been lost sight of, largely because of rough roads, hos- 

 tile public opinion, and the rapid development of steam 

 railways. 



A device for allowing the drive- wheels to travel at different 

 speeds is mentioned in the early 30's, but the differential gear 

 which has made the modern power vehicle so adaptable was 

 not perfected until about 1870, when Prof. R. H. Thurston 

 described it as "new and very neat." The friction clutch 

 soon followed, still further adding to the easy manipulation 

 of the tractor. From 1875 to the close of the century, develop- 

 ment in American steam tractors was very rapid. Their 

 utilization in plowing began almost as soon as they became 

 self-propelling. Their serious use for this purpose, however, 

 is not recorded until in the years just preceding 1890, when 

 scattered operators began to use the most powerful threshing 

 engines of that day for plowing, with only moderate suc- 

 cess. The steam engine is a century and a half old, but 



