268 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1907. 
T am talking to-night, in purpose at least, to the amateur; but my 
definition of the amateur is perhaps a broader one than is generally 
accepted. According to my view, the amateur is the man who works 
in astronomy because he can not help it, because he would rather do 
such work than anything else in the world, and who therefore cares 
little for hampering traditions or for difficulties of any kind. The 
“amateur,” then, is the person to whom I wish to address my remarks, 
whether he be connected with a small observatory in the capacity of 
professional astronomer, or working by himself with very simple in- 
strumental means. But in speaking to the amateur I do not wish to 
deal with work that shall be satisfactory merely from the standpoint 
of instruction or amusement. That is not my purpose. If it is possi- 
ble to carry on research by simple means that shall really be impor- 
tant and useful, itis my hope to point out some such possibilities. But 
I do not wish to speak of any work except that of the first class, nor 
to recommend that any investigations should be undertaken with sim- 
ple instruments that are not quite as important as other investigations 
which can be better undertaken with more expensivé instruments. 
The problem then becomes one of this character—to determine the 
relative advantages of large and small telescopes for different classes 
of research, and the possibility of constructing really powerful instru- 
ments at moderate expense. I can. not pretend to discuss all phases of 
this large problem; I shall mention only a few of them, and approach 
it from a single direction. But before taking up the details of this 
discussion, perhaps I may be permitted to say that the conception that 
is sometimes formed of the newer observatories, the idea that vast 
sums of money are expended, perhaps without the fullest sense of 
economy, is not always well founded. For I am quite sure that if you 
would visit us (to take a single concrete case) in California, you 
would agree that we have considered the economical side of the ques- 
tion, that we have perhaps in some instances gone almost too far in 
our desire to save money for instruments of research, and to economize 
in certain directions where money can be saved. For example, you 
would find that our offices, our buildings, are of the simplest and least 
expensive character, while our instruments and machinery are as 
effective as we can make them. The great expense of such an observa- 
tory as the Solar Observatory on Mount Wilson does not depend in 
large degree on the cost of the instruments used for investigations of 
the sun, but in surmounting the difficulties encountered in utilizing a 
mountain site, deprived of the ordinary means of transportation, and 
in the construction of large equatorial reflecting telescopes for stellar 
work, which can not be built cheaply if they are to be really efficient. 
I wish now to come to the question before us, and to illustrate 
some of the advantages and some of the disadvantages of large and 
small instruments. Perhaps you will permit me, in showing the 
