jflBoon Stufr 87 



greatly envy. At the same time, he does not altogether 

 admit that drawings are essential so long as the written 

 notes are sufficiently detailed, though, of course, an 

 accompanying sketch or two adds to the value of the 

 notes. There is certainly hope for us all when we learn 

 that the celebrated Schroter, who may be looked upon 

 as the Father of Selenography, was but an indifferent 

 hand with the pencil. 



Concerning mathematics as an alleged drawback, 

 Mr. Porthouse contends and very properly, too 

 that an absence of knowledge of them should not 

 stand in the way of lunar observation. Very little 

 mathematical computation is required for the work. 

 Neither, in regard to reason No. 3, is a giant telescope 

 necessary. " The most valuable lunar work appears to 

 have been accomplished with moderately sized instru- 

 ments," my correspondent says, " and the foundations 

 of selenography were undoubtedly laid with instru- 

 ments decidedly on the small side." Beer and Madler's 

 instrument was only 3|-in. aperture, and Neison's 

 great work on the moon was the result of long years of 

 labour with a 6-in. refractor. 



The absence of a set programme of work is, in Mr. 

 Porthouse's opinion, the greatest stumbling-block to 

 the lunar observer. Time is wasted on casual observa- 

 tions, which, being without definite aim, are unfruitful 

 of result. On this point, my correspondent offers the 

 following sound advice : " When choosing objects for 

 observation do not be tempted to range over too wide 

 a field. Rather devote your activities to the detailed 

 and systematic study of a limited number of forma- 

 tions, making a point of observing and sketching these 

 objects under as many differing angles of illumination 



