DELICATE SCIENTIFIC INSTRUMENTS. 743 
Jupiter and Saturn have approached so near the sun’s place that a good view 
of them cannot be obtained this month. On the 22d they are in conjunction 
with each other and also with the sun. 
Uranus is situated in the constellation Leo about 12° east and 4° south of 
Regulus, the brightest star of that constellation. If is now in a very favorable 
position for observation, and as only a few persons have ever seen this planet 
the present opportunity should not be missed. It shines with the light of a 6th 
magnitude star, and under the most favorable circumstances is visible to the 
naked eye. | 
Neptune is situated in the constellation Aries, but being so faint, owing to its 
enormous distance, cannot be seen except with good astronomical instruments. 
The Moon on the rst is in conjunction with Venus, passing south of that 
planet 3° 22’. On the roth it is within 6° 19’ of Uranus. By the 28th it will be 
again in conjunction with Venus, passing south 2° 40’, but both will be so near 
the sun that they cannot be seen with the unaided eye. i 
DELICATE SCIENTIFIC INSTRUMENTS, AND SOME RECENT 
RESULTS OF THEIR USE. 
BY EDGAR L. LARKIN, NEW WINDSOR OBSERVATORY, NEW WINDSOR, ILLINOIS. 
Within the last five years, scientific men have surpassed previous efforts in 
close measurement and refined analysis. By means of instruments of exceeding 
delicacy, processes in nature hitherto unknown, are made palpable to sense. 
Heat is found in ice, light in seeming darkness, and sound in apparent silence. 
It seems that physicists and chemists have almost if not quite reached the ultimate 
atoms of matter. The mechanism must be sensitive, as such properties of matter 
as heat, light, electricity, magnetism and actinism, are to be handled, caused to 
vanish and reappear, analyzed and measured. With such instruments, nature is 
scrutinized, revealing new properties, strange motions, vibrations and undulations. 
Throughout the visible universe, the faintest pulsations of atoms are detected, and 
countless millions of infinitely small waves, bearing light, heat and sound are dis- 
covered and their lengths determined. Refined spectroscopic analysis of light is 
now made, so that when any material burns, no matter what its distance, its spec- 
trum tells what substance is burning. When any luminous body appears, it can 
be told whether it is approaching or receding, or whether it shines by its own 
-or reflected light; whence it is seen that rays falling on earth from a flight of a 
hundred years, are as sounding lines dropped in the appalling depths of space. 
We wish to describe a few of these intricate instruments, and mention several 
far-reaching discoveries made by their use; beginning with mechanism for the 
manipulation of light. Optics is based on the accidental discovery that a piece 
of glass of certain shape will draw light to a focus, forming an image of any object 
at that point. The next step was in learning that this image can be viewed 
