The herald., 1897-03-28

The grinding and the polishing may
have cost twice as much more. Another
fact which is less understood is that the
large lens which forms the objective
of a telescope is not a magnifier, but
light gatherer. The magnification of the
image is done by the eye piece. 1t was
this fact, set off against the immense
cost of lenses of very great size, that
led an ingenious German inventor, now
living in Chicago, to the idea that in
stead of an objective formed of single
large lens he might make the latter in
sections, so to speak, and accomplish
the same result and even much more.
An increase in the area of the lens is
always at the expense of density and
clearness, so that at certain point the
ratio of power to area begins to decline
rapidly, until the limit is finally reached.
So far as man can now see this limit
has been reached in the Lick and Yerkes
telescopes. On the other hand, it is pos
sible to make small lenses, say of less
than six inches in diameter, of very
great accuracy, and rapidly and cheap
ly. In the Lowe telescope 100 or more
of these small lenses will be set either
in metal or Opaque glass to form an OBJ
jective from 60 to 72 inches in diameter,
the height of tall man. Yet more re-
markable, the focal length of this great
sectional lens will not correspond to that
of single piece lens of the same diane
ter, but will have focal length simply
of that of each of the sections. Thus,
while the barrel of the Lick telescope is
about 60 feet long, that of the Lowe tele-
scope will not be more than 10 or 20 feet.
The Philadelphia Evening TelegraDh
thus recounts an interview with Pro-
fessor Lowe, who has been visiting his
old home in Norristowr:
The professor was found in the room
where, twenty-five years ago, he in
vented his process for the manufacture
of water gas. This invention led to the
organization of the United Gas Improve
ment company of this city Zone of the
most important and wealthy organiza-
tions of its krid in the country. for the
purpose Of introducing Professor Loves
processes to the world; and, today a5
per cent of all the gas made in the United
States is made after his method. The
visitor, remarking that there was much
curiosity regarding the new telescope,
inquired of Professor Lowe whether he
was its inventor.
"NoI" responded Professor Lowe. "To
Mr.. Louis Gathmann of Chicago, that
honor belongs. He is a noted inventor
having originated guns, armor plate, and
variety of useful things now owned by
the United States government"
I'm what way does this telescope diff
fer from any other?" was asked.
made of two objective lenses, of the
same size, but of differently shaped sur
face and composition of glass. One is of
crown. the other of flint glass. These
two kinds of glass are used for the pur-
pose of removing the prismatic colors
which obtrude in a single lens and give
an indistinct object for each color, IN
stead of one clearly defined object, as
desired. So that when opticians or as
tronomenrs speak of the 36-inch lens IF
the Lick telescope, or the 40-inch lens of
the Yerkes, they really mean the two
lenses-the one of crown, the other of
f1int-that go to make up what is
spoken of as the objective lens of an
achromatic refracting telescope. Now,
by the Gathmann method, the crown
and flint lenses are used as in the ordi-
nary method; but, instead of the lens
being 36 inches in diameter, it is made
by filing up diameter of 36, 40 60, 70 or
even 100 inches. as desired, with large
number of smaller lenses all made of
good, clear glass, and ground to one
common focus.
you have a very fine climate in your