Accidents through Farm Machinery. 
:;r,r. 
by the drum. This may be cited as an instance of the increase 
of safety through the use of an improved material. 
2. The bad state of a machine from neglected repairs can only 
be, humanly' speaking, the fault of the employer. For however 
well made a machine, an engine, or a boiler, may be when it 
leaves the hands of the maker, no skill in its manufacture can 
compensate for neglect during its use. There is no more striking 
application for the well-known Spanish saying about the lost 
horse-shoe nail causing the loss of the horse than to an ill-kept 
boiler. A neglect of the repairs of a machine simply ends in its 
refusing to work. The pound saved in little repairs and " stitches 
in time " leads to the expenditure of 9Z. — perhaps 90/. — to meet 
the iron-founder's bill. In this instance, the employer has only 
himself to blame, and he suffers accordingly. But with a steam- 
boiler the evil is greater, for an explosion leads not merely to a loss 
of property, but also of life. The treatment undergone by agricul- 
tural boilers is indeed sometimes incredibly bad. The universal 
panacea for leakages appears to be cow-dung by the barrow-full, 
until, at last, the water spaces get filled with solid matter. It is 
only by walking the hospital of the repairing-shop of some agricul- 
tural implement maker that a fair idea may be gained of the way 
in which these engines are often treated. Nor do the boilers that 
have been repaired always leave the foundry in a safe state. A 
strict supervision should, as a rule, be given to repairs executed 
by contract. Many an explosion has happened from a bad patch. 
Those wishing for a sound explanation of these apparently un- 
accountable disasters may be referred to a little work on the 
question, by Mr. Zerah Colburn, C.E.* The intimate knowledge 
we now have of this subject — a knowledge greatly furthered 
by the systematic periodical examinations of the excellent Man- 
chester Association for the Prevention of Boiler Explosions — has 
led most engineers to the conclusion that (supposing the boiler to 
have been properly made) the originating cause of an explosion 
is simply the neglected state in which the boiler was kept. But 
few engineers now believe that there is much mystery in the matter. 
In the simple weakening of a plate — either through undue 
pressure at some time or other, or through corrosion caused by 
leakage, or through neglected incrustation, or through burning 
a plate by letting the water get too low ; through one or more of 
such causes — is a boiler explosion originated. Perhaps the 
rupture happily occurs below the water line, and then the water 
is simply gradually forced out, doing little or no damage. But 
not so when the rupture occurs above the water line. The super- 
incumbent pressure is suddenly released from a large volume of 
* Steam-Boiler Explosions. London : John Weale, 1860. 
