As in gas engines, a current of water is made to flow around the cylinder, C', in order to keep the sides from getting too hot.
In order to set the engine in motion, we begin by opening the bottom, C, of the cylinder, C', to clean the grate. This done, we close C and introduce lighted charcoal through the conduit, c' (the valve being open). The valve is put in place, two or three revolutions are given to the fly wheel, and the motor starts. The feeding is afterward done with coke.
The parts that transmit motion operate under conditions analogous to those under which the same parts of a steam engine do. The air pump sucks and forces nothing but cold air, and nothing but cold air passes through the distributing slide valve. The pump and valve are therefore rendered very durable. The piston and cylinder, at the points where friction exists, are at a temperature of 60 or 80 degrees. These surfaces are protected against hot gas charged with dust.
The hot gas, which escapes from the cylinder through a valve, has previously been cooled by contact with the sides of the cylinder and by expansion. The eduction valve just mentioned works about like that of a steam engine, and it is only necessary to polish it now and then in order to keep it in good condition.—Annales Industrielles.
YOUR FUTURE PROBLEMS.[1]
By CHARLES E. EMERY.
Mr. President and Ladies and Gentlemen: It has not been considered the duty of the speaker, in addressing the graduating class, to dwell on the triumphs of science or the advantage of a liberal education. These subjects have already been discussed, in connection with the regular courses of study, better, and more at length, than he could do. We propose rather to try and prepare the minds of the graduates for the practical problems before them.
All young men are impressed with the consciousness of higher powers as they increase their stores of knowledge, and this feeling perhaps reaches its maximum with those who have made a specialty of the investigation and application of physical laws. Young men who have learned how to harness the powers of nature and guide them to do their will are apt to belittle the difficulties they have yet to overcome, and have a false impression of the problems of life. This feeling is shown to a minimum extent by graduates of the Stevens Institute, on account of their careful practical training, in connection with the thorough study of principles; but it has been thought best for one from the outside world to supplement such teaching by calling to mind instances which may have a useful counteracting effect, and, like parables, serve the purpose of illustrative instruction.
Gentlemen of the Class of '87: It was the pleasure of the speaker to address the class of '79, under the title of "How to Succeed," some words of counsel and warning, which, if they left an impression of severity at the time, were apparently so well received afterward that he has been tempted to continue the general subject, with the title of "Your Future Problems." The notation of your future problems will not be found at once among the known quantities, but with x, y, and z, at the other end of the alphabet. Often word symbols will be applicable, expressing at times disappointment and pain, at other times renewed effort, and finally the active phases of individual thought and exertion.