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, The patent boilers of the engines will 

 after every precaution is taken, become be perfectly clean not only for many 

 coated with hard scale of considerable voyages but for years, and their dura- 

 thickness ; this being a bad conductor of bility will be very much greater than 

 heat prevents the free transmission thereof that of boilers supplied with salt water, 

 from the fires to the water, causes the and a comparatively small consumption 

 boilers to burn and wear out very of fuel will also be the result. 



rapidly, and greatly increases the con- 

 sumption of fuel. 



5. In order to prevent the boilers of In the patent engines, all delays and 

 injection engines from burning and wear- inconveniences arising from the empty- 

 ing out with a rapidity that could not be ing and clearing of boilers are entirely 

 submitted to, it is necessary in long superseded, for by their permanent clean- 

 voyages to suspend the working of the ness, the water they contain entirely de- 

 boilers in order to empty and cool them, fends them from the action of the fire, 

 for the purpose of clearing away and and as no deposit takes place, they are 

 chipping off the scale that firmly adheres not subjected to the injury caused by 

 to them, which operation considerably chipping off scale, as in injection engines, 

 injures the boilers. 



6. In injection engines, the oil which In the patent engines, not a particle of 

 is put into the cylinders, stuffing-boxes, the oil which is given to the internal parts 

 slides, &c., is speedily carried away by of the engine, &c., is washed away into 

 the injection water into the sea ; the time, the sea or lost, but it is all carried into the 

 therefore, of its being in the engines is so boilers, whereby they are protected from 

 short that nine tenths of it is wasted and corrosion, and an ample lubrication of the 

 does but little if any good, and it does not, engines is effected at scarcely any cost, as 

 as in the patent engines, enter the boilers hereafter mentioned. 



and protect them from the corrosive ac- 

 tion of hot salt water. 



7. In injection engines, a portion of the In the patent engines, a portion of oil 

 salt contained in the water is carried over being always, as before stated, introduced 

 mechanically along with the steam into in commixture with the pure water into 

 the working cylinders, slowly corroding the boilers, it passes over mechanically 

 and wearing the slides, valves, and other along with the steam in minute parti- 



