Evening star., 1914-11-24

ing more about Mars, the planet which
for centuries has fired the imagination
not only of scientists, but of all hu-
| manity. 1t is we'll known that the
surface of Mars is thought to be cut by
immense canals. which appear to have
been the work of intelligent beings.
and which, If such is the case. would
indicate that the Martians have car
ried science Of engineering to Pc =
fection which would make the achieve
ments of the human race in that line
would be as a small ditch beside the
canals of Mars.
1t has been found that heat radiated
from water will give a slightly differ
anism from that given by heat radi-
ated from solid body. In this way it
is possible that the truth may be
learned about he canals OF Mars. and
even that something may be ascer-
tanned as to the rest of its surface.
which has been thought by some as
tronomers to be covered with red veg
citation
So much for the value OF measuring
star heat to astronomy and science at
large. And now, back to earth. The
most obvious value OF the invention
from a utilitarian point of view lies In
the fact that II is wonderfully sensi-
tive and accurate instrument for meas
uring heat. Such an instrument Is
called a radiation pyrometer. 1t Is used
for such ordinary and mundane pur-
poses as measuring the heat of blast
furnaces and rolling mill billets. Mr..
Coblent1e has primarily perfected a
radiation pyrometer several hundred
which is capable of registering a mil
lionth of degree of heat. and 1t will
have a variety of uses in the Industrial
world.
One part of the complete mechanism
for measuring star heat is a water
cell. through which
Elimination Of the light Of the
Invisible Rays. o1a.s ora., rs to pasosG eliminate tn
certain of the invisible rays. In the
course of his experiments with this
part of the mechanism Mr.. Coblentze
found that II instead OF a square cell
Allied merely with water a solution of
copper chloride was used. a large num-
Der OF the invisible rays of the spec
trum are eliminated. About that time,
a manufacturer of moving picture ap-
ards, asking II there was any kind of
a cell by which the flm could be more
effectively protected from the heat of
the arc light than by an ordinary water
cell Mr.. Coblentze was able to tell
him about the use of the copper
chloride solution. By placing cell
this solution between the
film and the light which throws the
picture on the screen 1t Is possible to
eliminate the heat OF some Of the in
visible rays without losing the light
from the visible ones. Thus did the
movies get a boost from the measure
ment OF starlight.
Although the mechanism OF this in
strument Is almost inconceivably deli
cate. the basic principle OF 1t is quite
simple and comprehensive to any one
who understands the fundamentals Of
electricity. The vital part Of the in
strument consists In two very delicate
wires of different metals, either bis
muth and silver or platinum and sill
YER, soldered together, and Of a tiny.
heat bsorbing surface. painted with
lamp black and placed over the juno
tion of the two wires. When this sur
face is exposed to heat, the two wires
will generate an electrical current upon
exactly the same principle as an ordi-
nary electrical battery. The distinctive
thing about this battery is its extreme
delicacy, which makes it hard for the
average beholder to believe that it is
the work of human hands. 1t is this
delicacy which makes it sensitive to
the very slightest changes in tempera-
ture.