
          which may now be screwed into the place prepared
in the solid piece of brass a b, and will be as
represented in fig. 4. Now if c represents the tube
which leads to the generator, and to the tube
hacking into the [?] air or another [?],
it appears plain that when closed the [?]
first will be sufficient to furnish the escape of
the gas, and by starting the thumb screw m
the gas is permitted to pass out but can escape in
no other direction! Will it work? And is it
better or worse than the double conical stop
cock?

We have met with an irreparable loss
in the death of our an [?] president, Dr. [Wilbur] Fisk.
Your letter came hiding his illness; and on being
presented with your kind salutations, he expressed his
regard for you and wished to be remembered to you
when I should write again.

Very respectfully 
John Johnston

John Torrey M.D.
        