DELICA TE SCIENTIFIC INSTRUMENTS. ' 749 
This huge photograph can be viewed in detail with a small telescope and microm- 
eter, and the crests of solar waves measured. Many of these billows of fire are 
in dimensions every way equal in size to the state of Illinois. Binary stars are 
photographed so that in time to come they can be re-taken, when if they have 
moved, the precise amount can be measured. 
Another instrument is the Telepolariscope, to be attached to a telescope. It 
tells whether any luminous body sends us its own, or reflected light. Only one 
comet bright enough to be examined has appeared since its perfection. This was 
Coggia’s, and was found to reflect solar from the tail, and_to radiate its own light 
from the nucleus. 
Still another intricate instrument is in use, the Thermograph, that utilizes the 
heat rays from the sun, instead of the light. It takes pictures by heat; in other 
words it sees in the dark ; brings invisible things to the eye of man, and is used 
in astronomical and physical researches wherein undulations and radiations are 
concerned. And now comes the Magnetometer, to measure the amount of mag- 
netism that reaches the earth from the sun. * It points to zero when the magnetic 
forces of the earth are in equilibrium, but let a magnetic storm occur anywhere in 
the world and the pointer will move by invisible power. It detects a close re- 
lation between the magnetism of the earth and sun. The needle is deflected 
every time a solar disturbance takes place. At Kew, England, an astronomer was 
viewing the sun with a telescope and observed a tongue of flame dart across a 
spot, whose diameter was 33,700 miles. The magnetometer was violently agita- 
ted at once, showing that whatever magnetism may be, itsinfluence traversed the 
distance of the sun with a velocity greater than that of light. 
Not less remarkable is the new instrument the Thermal Balance devised by 
Prof. S. P. Langley Pittsburg. It will measure the 1-50.000 part of a degree of 
heat, and consists of strips of platinum 1-32 of an inch wide and ¥Y of an inch 
long ; and so thin that it requires fifty to equal the thickness of tissue paper, placed 
in the circuit of electricity running to a galvanometer. ‘‘When mounted in a 
reflecting telescope it will record the heat from the body of a man or other animal 
in an adjoining field, and can do so at great distances. It will do this equally 
well-at night, and may be said, in a certain sense, to give the power of seeing in 
the dark. (‘‘Science,”’ issue of Jan. 8, 1881, p 12.) It is expected to reveal great 
facts concerning the heat of the stars. 
Indeed, the Thermopile in the hands of Lockyer has already made palpable the 
heat of the fixed stars. He placed the little detective in the focus of a telescope 
and turned it on Arcturus. ‘* The result was this, that the heat received from 
Arcturus, when at an altitude of 55°, was found to be just equal to that received 
from a cube of boiling water, three inches across each side, at the distance of 400 
yards ; and the heat from Vega is equal to that from the same cube at 600 yards.” 
(Lockyer’s Star Gazing, p 385.) Thus that inscrutable mode of force heat, traverses 
the depths of space, reaches the earth, and turns the delicate balance of the ther. 
mopile. Another discovery was made with the spectroscope; thus, if a boat 
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