EXPLANATION OF THE PLATES. 
373 
every two or three hours, which cold 
water, having to be brought up to the 
boiling point, causes a considerable waste 
of fuel to take place. 
4. In injection engines, the boilers will, 
after every precaution is taken, become 
coated with hard scale of considerable 
thickness ; this being a bad conductor of 
heat prevents the free transmission thereof 
from the fires to the water, causes the 
boilers to burn and wear out very 
rapidly, and greatly increases the con 
sumption of fuel. 
5. In order to prevent the boilers of 
injection engines from burning and wear 
ing out with a rapidity that could not be 
submitted to, it is necessary in long 
voyages to suspend the working of the 
boilers in order to empty and cool them, 
for the purpose of clearing away and 
chipping off the scale that firmly adheres 
to them, which operation considerably 
injures the boilers. 
6. In injection engines, the oil which 
is put into the cylinders, stuffing-boxes, 
slides, &cc., is speedily carried away by 
the injection water into the sea; the time, 
therefore, of its being in the engines is so 
short that nine tenths of it is wasted and 
does but little if any good, and it does not, 
as in the patent engines, enter the boilers 
and protect them from the corrosive ac 
tion of hot salt water. 
7. In injection engines, a portion of the 
salt contained in the water is carried over 
mechanically along with the steam into 
the working cylinders, slowly corroding 
and wearing the slides, valves, and other 
The patent boilers of the engines will 
be perfectly clean not only for many 
voyages but for years, and their dura 
bility will be very much greater than 
that of boilers supplied with salt water, 
and a comparatively small consumption 
of fuel will also be the result. 
In the patent engines, all delays and 
inconveniences arising from the empty 
ing and clearing of boilers are entirely 
superseded, for by their permanent clean 
ness, the water they contain entirely de 
fends them from the action of the fire, 
and as no deposit takes place, they are 
not subjected to the injury caused by 
chipping off scale, as in injection engines. 
In the patent engines, not a particle of 
the oil which is given to the internal parts 
of the engine, &c., is washed away into 
the sea or lost, but it is all carried into the 
boilers, whereby they are protected from 
corrosion, and an ample lubrication of the 
engines is effected at scarcely any cost, as 
hereafter mentioned. 
In the patent engines, a portion of oil 
being always, as before stated, introduced 
in commixture with the pure water into 
the boilers, it passes over mechanically 
along with the steam in minute parti-