to the Cultivation of the Land. 
207 
siderable weights along common roads, sucli as its own ploughing- 
tackle, and sometimes about 4 tons of coal on a common waggon. 
In October, 1857, Mr. Smith made a portable 6-horse locomotive 
engine lor Messrs. S. and G. Lewis, of Audley, near Newcastle, 
Staffordshire, and the following is their account of its working : — 
" Onr locomotive tlircsliiug-en<:ine gives us perfect satisfaclion. The 
neighbourhood of Audley is very hilly ; and sometimes ve. have to go up, not 
only long, but steep hills, when the engine takes itself and machine, with one 
horse to guide it and help to draw. We do not lind it difficult to go on the 
common roads, and make the usual turns, some of v/hich are rather sudden. 
We find especial convenience in thus moving I'roni place to place at times 
when persons are busy with their horses, or would object to take them out so 
late in the evening ; and as we can move in the evening after thi'eshing our 
day's work, sometimes several miles, the ensine lias saved us the loss of many 
a day since we have had it. Indeed, we have thnished at two or three places 
in one day, and so saved much time in emptying and refilling the boiler, as 
we otherwise must have done. And then we consider that this engine will 
last longer than an ordinary one, as it is not so fi-eqnently subjected to sudden 
contraction on the tube-plates, as we do not need to empty it more than once 
a month. And, again, we think it travels better along the common roads 
than it would do without steam (the water and pressure in the boiler tending 
to relieve the tubes of the jar which they are subject to when the boiler is 
travelling empty over a jolting surface). We steam up in a few minutes 
ready for work, and as the convenience of our engine obtains for us an extra 
price of 5s. per day more than an ordinary engine, and gets iis many cus- 
tomers which we should not otherwise have had, this must make a very con- 
siderable item of profit in the course of a year. We have had full work for it, 
when other engines for hire were long standing out of work." 
In traversing alternate hills and hollows in quick succession, 
it appears that the tubes and fire-box of a boiler are not liable 
to any special injury — the momentary displacement of the level 
of the boiler not allowing time for the portions of heating-surface 
(left bare by the water) to become dangerously hot ; and when 
a slanting position occurs for a longer time togetlier, upon 
moderate inclines, the " swill " of the water with the irregular 
motion of travelling seems to keep tlie exposed parts sufficiently 
cool. Of course, a boiler constructed with flues as well as 
tubes is less subject to damage than one in which tubes take the 
heated air and flame directly from the fire-box. To escape 
leakage, burning, or explosion, when the engine is required to 
stand for a long time together on the sloping headland of a field 
(as in working Fowler's plough in a hilly country), or in case 
of delay and detention upon a steep gradient, there must be either 
some means of adjusting the level of the boiler or the boiler 
must be of peculiar construction. 
Mr. Smith has contrived an engine which can operate with- 
out detriment upon the steepest inclines that its power may 
enable it to climb, either by its own locomotive action or 
by the slower motion and stronger purchase of a barrel and 
