366 EXPLANATION OF THE PLATES. 



alleged triumphs is owing to the use of high pressure steam, used expansively ; 

 the causing the pistons of very long stroke engines to move at the rate of 300, 400, 

 and sometimes 600 feet per minute ; and lastly, to the superior form of the bows 

 of their steamers, which are built so as to glide over the water instead of cutting 

 through it. 



In the case of the Ruby, in all these important matters she is decidedly the re- 

 verse of the Americans; the piston only travels about 210 feet per minute, very low 

 pressure steam is used, the stroke of the engines is very short, being only two inches 

 more than the diameter of the cylinder, and the form of the bow is decidedly that 

 which will cut or divide the water without the least tendency to ride over it, inas- 

 much as this vessel's bow is shaped like a knife, being as long on the keel as at the 

 water's edge within two feet. 



Judging from these facts, it will be seen that high pressure steam, length of stroke, 

 and prow-shaped bows, qualities so loudly extolled by the Americans, are not all 

 necessary for speed, but on the contrary, the first two are positive nuisances ; the 

 length of stroke rendering the vessel an unwieldy, ill-contrived machine, totally use- 

 less for the purposes of sea navigation, as events have proved ; while the high 

 pressure steam system has been the means of filling the journals with those ever- 

 occurring, heart-rending, and sickening details of hundreds and thousands that are 

 being yearly sacrificed to ignorance and prejudice, by attempting to do that by the 

 dangerous use of high pressure steam which can be so well effected by steam of a 

 low pressure, and that too at one half the consumption of fuel. 



The limits of this paper will not permit the writer to digress upon the subject of 

 consumption of fuel, except by stating, that in no instance has the use of high pressure 

 steam applied to an engine for rotary purposes ever been attended with economy of 

 fuel, but the reverse ; and it is not a little singular, that in this age, even in this year, 

 northern engineers are imitating the Americans, by the use of the long stroke and 

 high pressure steam, in the Thames, which one would think might have been spared 

 this pestiferous curse. The results have been, and are, that the short stroke engines 

 are propelling the boats, both sea and river class, faster than the long stroke ones. 

 This length of stroke has been obtained by the placing of one half the machinery 

 upon deck, some 12 or 14 feet high, and thus making the vessel frightfully crank and 

 most unseemly to look at, while in vessels going head to wind, it exposes some 

 hundreds of square feet of surface to be acted upon as a back sail. 



The great danger of high pressure steam will be evident to every one, when it is 

 recollected that within the last three years, three different vessels have had dreadful 

 explosions, viz., two on the Thames and one at Greenock, (besides some less fatal 

 ones in different parts of the north,) by which more lives have been sacrificed to the 



