THE DESIGN OF AN OIL ENGINE. 33 
given out and the navigator has had to stand by and watch his vessel strike in a 
way which must be particularly annoying to a good navigator. This feeling of un- 
certainty as to the condition of the air supply must do much to make the oil en- 
gine unpopular with the bridge force. On the other hand the use of steam drawn 
_ from the auxiliary boiler would do away with all this, and the navigator need not 
know but that his engine is a steam engine. He can come within maneuvering 
distance of the dock and then go on to the maneuvering cycle and bring his vessel 
up to the pier with absolute assurance. In order to make this possible in the oil en- 
gine it is necessary only to provide the engine with means for jacketing the cylin- 
ders with live steam. In fact, for the last case considered—that is, of maneuvering 
to come to a dock—it will be necessary only to cut out the cooling water and to de- 
pend upon the heat of the cylinder walls to prevent undue condensation. This is 
not a condition which need offer much difficulty, as the engine will simply follow 
the practice of the present steam engine. 
The whole idea of this design is to reconcile the peculiarities of the oil engine 
to that thermodynamic practice which has been found to be best in the use of the 
steam engine. The cylinder walls of the engine are jacketed, not to make them 
cold, but rather to prevent them from becoming too hot. It seems to be a necessary 
line of development to study this matter of temperature of the engine and to see that 
the engine be not reduced in temperature below that point which is desirable, just 
as in the steam engine the point of the best practical vacuum becomes a matter of 
judgment and not a case of obtaining the greatest possible vacuum regardless of 
cost. 
THE ACTUAL DESIGN SUBMITTED. 
In presenting this design no attempt is made to claim perfection. The aim has 
been to present a design which will be a basis for improvement. It is felt, how- 
ever, that to submit general ideas without presenting working plans is apt to leave 
the reader in doubt as to how the general scheme will work out. If this design 
starts thought and discussion it will not fail of its purpose. It is felt by the author 
that the design submitted is superior to any of which he is aware. At the same 
time it is fully recognized, that with so much detail as is found in such a design, 
many of the minor details can be wisely criticized. It is felt that such can be im- 
proved upon or altered without altering the type of the engine. 
The general ideas have been presented first, in order to make clear the aim of 
this type of engine. This design is a four-cycle type, but many of the principles in- 
volved can be applied to a two-cycle type, although the four-cycle is favored by the 
author. If the elements taken up are found to be sound, the practical application 
of these elements to a design of different size and use will be a matter of applica- 
tion of recognized principles rather than a matter of design along new lines. It 
has been hoped that it would be possible to make it perfectly clear that an oil engine 
can be designed in the same manner as a steam engine, and that it is not necessary 
to buy experience from foreign manufacturers. It has been hoped that this paper 
