122 REPORT—1849. 
again raised by the steam, must, in falling, have given back the force which raised 
it, minus that which is destroyed by friction at the axle, and which, from the latter 
merely resting, as we have seen, on its bearings, must be inconsiderable. 
At first we experienced much inconvenience from the difficulty of getting the 
steam conveniently in and out of the axle, since we were not satisfied with the 
arrangements employed with the oscillating engine. But we found that this dif- 
ficulty might be removed, by a valve of great simplicity—and which has now been, 
for a considerable time, working most effectively.—It has but little friction, because 
it is exposed to equal and opposite pressures, and its rubbing surfaces are metallic. 
This engine works equally well in either direction, and may be reversed without 
turning off the steam, by means of a handle—seen in the figure over the standard 
Q, and a little to the right-hand. 
The details may be varied in a great many ways. The weights may be placed 
respectively at the extremities of the piston-rod, trunnions being cast or bolted on 
the centre of the cylinder. The weights themselves may act as cylinders, the steam 
being transmitted through hollow piston-rods, fixed to the hollow axle. Also a 
single cylinder, moving backwards and forwards on a hollow piston-rod, having the 
piston in its centre,—and a variety of other modifications may be employed ; but the 
form exemplified by the model working at this moment before the Section, has the 
advantage of resembling, in almost all its details, the simplest form of the ordinary 
engine. 
On an Instrument called the “ Upton Draining Tool,” as illustrating a prin- 
ciple by which the resistance of Soils to Agricultural Implements may be 
considerably diminished. By A. Mitwarp. 
When we consider the rudeness of the agricultural implements in actual use over 
a great part of the country, and the want of fixed principles in the construction of 
the more complicated kinds, it may not perhaps be altogether useless to draw atten- 
tion to a general cause of resistance to the efficient working of agricultural tools, 
and to show how, in the use of a particular tool, that cause of resistance has been 
very materially diminished. 
It is not until very recently that the accurate researches of science have been 
brought to bear on the practical operations of agriculture. The services of chemistry - 
have, it is true, been great; the experiments and energy of Mr. Josiah Parkes and 
others have thrown considerable light on the action of water upon soils, and thence 
established certain principles of draining; and skilful mechanics have materially 
improved our old implements, and invented many others of very great utility. But 
much, nevertheless, remains to be done in determining the nature and extent of some 
of those natural causes which it is the business of the farmer to overcome or turn 
to his own advantage. The laws of capillary attraction,—the porosity and fineness 
of division of different kinds of matter, particularly as connected with the former 
subject,—the phznomena of friction and adhesion,—have been so little investigated, 
that it is impossible to apply them with any exactness, or draw satisfactory conclu- 
sions from them. All these subjects are nevertheless intimately connected with the 
processes of agriculture; but it is unfortunately but too true that the ignorance of 
practical men, and the indifference of men of science, leave them to undeserved 
neglect. 
The cause of resistance, to which I have alluded above, is what I may distinguish 
by the name of after resistance, by which I mean resistance arising from the friction 
of the after parts of an instrument when dragged through or over the ground. If 
we take the case of the common spade, we find that it requires very little force to 
cause it to enter an inch into a stiff soil; but as it descends, the closing of the elastic — 
soil around it occasions so great a friction and adhesion along the after part of the 
tool, that a strong man is soon unable to drive it further. If, on the contrary, the 
spade be driven in on the side of an open cutting, the slice of earth cut off falls for-_ 
ward, the after resistance is much diminished, and the facility of working sufficiently — 
marked. This simple consideration points out to us the utility of providing that 
the fore-part of any instrument for penetrating the soil shall as much as possible 
detach the soil from the parts around, and so prevent their closing upon the tool and 

