WESTERN UNION TEL. 00. U. BALTIMORE & O. TEL. ®.d  
cial lines and the earth," it was obviouslybroader than the claim
which is now in controversy.
The claim in controversy is not enlarged by reason of any undue
enlargement of the descriptive part of the specification of the reis-.
sue. Mr. Renwick, an expert for the defendant, in his affidavit, says
that he agrees with Mr. Palmer, (another expert for the defendant,)
whose affidavit he has read, "that all the additional descriptive mat-
ter which describes more fully and completely the operation and uses
of the condenser, and the structure of the condenser, is legitimate,
and, although not necessary, does not widen the invention described
in the original patent." He goes on to say that the patentee enlarges ‘
his general preliminary statement of the character of his invention,
because in the original patent "he states, in substance, that the inven-
tion consists in placing a condenser in a certain branch circuit," while
the reissue "states, in substance, that the invention consists in pro-
ducing artificial currents of static charge and of static discharge at ·
the home station, and causing the same to occur simultaneously with
those from or on the main line, and that, therefore, the effect of the
latter can be practically eliminated." What the patentee does state
in his original is this:
" This invention is an improvement upon apparatus for transmitting two
signals at the same time from opposite ends of the same line wire,—its object
being to prevent the effect upon the relay at the sending station of the return
current, due to the static induction of the line; and it consists in the connec-
· tion, with the apparatus, of a condenser with any of the well-known forms."
· In the first reissue the statement is as follows:
" This invention relates to duplex telegraph apparatus,-its object being to
. neutralize the effect of the return current from the line on the relay or re-
ceiving instrument when the line is put to work; and to edect this the inven- V
tion may, in general, be stated to consist in the mode of accomplishing this
result by establishing, in a branch or compensating circuit, connected to the
circuit of the compensating helix of the relay, during the time that the lipe is
put to work, a return current, which will neutralize the effect of the return
current, from the line upon the line-helix of the relay, substantially in the
manner hereinafter described."
Mr. Benwick’s criticism upon the preliminary statement of the nat- .
ure of the invention contained in the second reissue is that no men-
tion is made in it of a condenser, and no assertion that theinvention
is based upon the use of a condenser, although it is stated afterwards
that the result may be conveniently effected by the use of a condenser.
Obviously this criticism has no force when applied to the claim in
controversy, because the claim makes the condenser an element of
the combination. A condenser having its terminals, respectively, con-
nected with the artificial or compensating line of the combination is
precisely what is described in the claim of the hrst reissue as a con-
denser “with a branch or compensating circuit, * * ** substan-
tially as and for the purpose herein specified/’ The only distinction
between the two things which is emphasized in the argument of coun-
v.25F.no.1-3