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]

  [Footnote 1:  An address to the graduating class, Stevens
  Institute, Hoboken, N.J., 1887.]

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.