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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 onty 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