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242 POPULAR SCIENCE REVIEW. 
between the different delineations of the same hand, for every 
observer has his own way of seeing and interpreting as well as 
of delineating what lies before him ; but ultimately a more 
extended collation would be requisite. To Mr. Birt, as editor 
of the “ English Lunar Map,” now in progress, our own observers 
would naturally refer for the safe preservation and general 
comparison of their united labours ; but it is obviously im- 
portant that what is thus communicated should be the result, 
not of rough and hasty attempts, but of careful and attentive 
delineation. It is also very desirable that such a representa- 
tion should be accompanied by a list, as well as by some 
description, of the objects delineated ; this being the most 
effective method of ensuring certainty to the evidence, and ! 
making it fully dependable for future comparison and in- 
ference. 
It may have been noticed that no allusion has been made to i 
the representation of those well-known streaks and specks and j 
clouds of white and grey which give so peculiar and un- 
intelligible a character to the aspect of the Lull Moon. The ■ 
delineation of these would be found in one respect more diffi- ^ 
cult, as requiring wider gradation of tone ; in another easier, i 
from the greater permanency of the object. It has been I 
hitherto little attempted in detail, but is well worthy of sepa- ■ j 
rate study. We have not space to enter now upon its cha- j 
racteristics, which indeed have been but very imperfectly ' 
investigated. Here also, however, indications of decided > 
change have not been wanting ; and the diligent and per- ; 
severing explorer would probably be rewarded in the end. 
