46 - rmnmnn. nnromnn.
needed; that the gas has great elasticity; that it is heavier than air, \
- and whencombined with water has a specific gravity well adapted
to pass in a stream through the air; that if any of the gas does by
any means reach the flame or fire it will not support combustion, but
has a direct operation in extinguishing the fiame and checking the
combustion. All these merits claimed by him have been tested in
- actual use for many years, and the utility of the invention has created
a large demand for the apparatus. With the utility thus established,
  I canrsee nothing fatal to the patent in the fact, if fact it be, that the
inventor may perhaps have overrated the importance of some of the
V elements of his method and underrated others.
With regard to the third point, that the patent is for a different in-
vention from that described in the original application, after careful
consideration I fail to see the force of the objection.
My conclusion is that Graham was, as is claimed for him, the pio-
neer in the art of using mingled carbonic acid gas and water to extin-
guish fires, and w_as the first to discover that when condensed in a
sufficiently strong vessel it would propel itself by its own elasticity to
f a. sufficient distance and in a sufficient stream to be a useful agent
for that purpose, and that he described both a portable and fixed ap-
paratusby which the result could be accomplished.
I hold the hrst and fourth claims of the patent to be valid, and in
my judgmentit is immaterial in this case whether my doubts as to
the validity of the other claims are well founded or not.
‘ There is no difficulty as to the infringement. The defendants can
hardly be said to directly deny it in their answers. The defendant
Johnston practically admits the making of six portable and six sta-
tionary machines, and says he desisted after being warned that they
were infringements. The circulars and advertisements of the other
defendant, in connection with the oral testimony, sufficiently show
the infringement by it, and that the machines complained of con-
tained the exact method of Graham, applied in substantially the same
apparatus described by him.
The complainants are entitled to a decree in their favor, and to a
referencefor an accounting. Sec, also, Fire-extinguisher Mamufg
Oo. v. Graham, 16 Fan. Bur. 543.