252 The Evolution of Ayricnlhtral Implements. 
of Boston to bring out a portable steam-threshing machine as early 
as 1839. They did so in 1842 ; but, meanwhile, Ransomes of 
Ipswich became entitled to the credit of showing the first port- 
able engine at the Liverpool Meeting of the Royal Agricultural 
Society in 1841. This was a two-wheeled affair ; followed, how- 
ever, by a four-wheeled engine, exhibited by the same firm at 
the Bristol Show of 1842, where three other engines on wheels 
made their first appearance. 
Ten years after the exhibition of the first poi-table engine, 
a writer in this Journal for 1851 estimated the number of 
these motors in the United Kingdom at 8,000, whde, at the 
present time, adding exported agricultural engines to those 
which have remained at home, these are, together, as the sands 
of the sea in number. At least 5,000 agricultural engines of 
various kinds are now manufactured annually in this country. 
Under the stimulus of competitive trials the portable engine 
realised a great economy in coal at a very early period, and the 
progressive record of the Royal Agricultural Society is very 
significant of the influence which the prize system had in 
bringing this about. The prize engine of 1849 burned 11^ lb. 
of coal per horse-power per hour ; that of 1850, 7| lb. ; of 1852, 
4f lb. ; of 1853, 41 lb. ; of 1855, 3| lb. ; of 1856, 3i lb., and 
of 1872, 2 '8 lb. The more remarkable of these results were ob- 
tained by crowding the boiler with tubes, by pinching the area 
of the firegrate to such a degree that only a trained stoker could 
keep his steam, and by using refined expansion gear requiring 
skilled handling. Such engines soon became known as “ racers” 
and were never supplied to farmers, the “ commercial ” engine 
which was sold always averaging a consumption of coal about 
double that of racing engines. 
The fact that the farmer is still practically without an 
economical engine has recently led to the introduction of com- 
pound portable engines, which effect all the economy obtained 
by the “ racers,” while using boilers of good construction 
and simple valves. The first compound engine ever seen at a 
Royal Show was exhibited by Messrs. John Fowler and Co., at 
Kilbum, in 1879. It was, however, only semi-portable, and it 
was reserved for Messrs. Garrett and Sons to bring out the first 
portable compound engine at Carlisle in 1880, a lead which has 
been quickly followed by several eminent makers. It was a com- 
pound engine, by Messrs. Davey, Paxman, and Co., that beat all 
previous records of economy at the Newcastle trials of 1887, while 
conclusively proving the suitability of this type of engine for use 
on the farm. 
Straw-burning engines are now largely used in countries where 
