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HOW TO WORK WITH THE TELESCOPE. 
PART I. 
PRINCIPLES OP CONSTRUCTION HOW TO TEST THE TELESCOPE. 
BY RICHARD A. PROCTOR, B.A., F.R.A.S., 
AUTHOR OF “ SATURN AND ITS SYSTEM.” 
Could I purchase it with travail, or procure it for gold, I would not he 
without a telescope. — Crabtree. 
T HE student of astronomy is often deterred from telescopic 
observation by the consideration that in a field in which 
so many have laboured, with abilities and means perhaps far 
surpassing those he may possess, he is little likely to reap 
results of any utility. He argues that, since the planets, stars, 
and nebulas have been scanned by Herschel and Rosse with 
their gigantic mirrors, and at Pulkova and Greenwich with 
refractors whose construction has taxed to the utmost the 
ingenuity of the optician and mechanic, it must be utterly 
useless for an unpractised observer to direct a telescope of 
moderate power to the examination of those objects. 
How passing over the consideration that a small telescope 
may afford its possessor much pleasure of an intellectual and 
elevated character, even if he is never able by its means to 
effect original discoveries, two arguments may be urged in 
favour of independent telescopic observation. In the first 
place, the student wdio would rightly appreciate the facts and 
theories of astronomy, should familiarize himself with the 
nature of the instrument to which astronomers have been 
most largely indebted. In the second place, some of the most 
important discoveries in astronomy have been effected by 
means of telescopes of moderate power, used skilfully and 
systematically. One instance may suffice to show what can 
be done in this way. Goldschmidt (who commenced astro- 
nomical observation at the age of 48, in 1850) has added 
fourteen asteroids to the solar system, not to speak of im- 
