324 THE EARL OF ROSSE’S OBSERVATIONS ON SOME OF THE NEBULA2. 
character has become clearly developed, as in fig. 26, and a further increase of power 
has shown the object resolved. 
It is also perhaps important to observe, that now, as has always been the case, an 
increase of instrumental power has added to the number of the clusters at the expense 
of the nebulae, properly so called ; still it would be very unsafe to conclude that such 
will always be the case, and thence to draw the obvious inference that all nebulosity 
is but the glare of stars too remote to be separated by the utmost power of our 
instruments. 
The magnifying powers I have usually employed vary from 250 to 800 ; occasionally 
much higher powers have been useful ; but to see everything described in this paper, 
a power of 600 with perfect definition is sufficient. 
In my paper on the Reflecting Telescope, in the Philosophical Transactions for 
1840, there is an error which I am anxious to take this opportunity of correcting. 
In page 523, line 14, instead of “to the polisher,” it should have been “to the bar 
which moves the polisher measured on the edge F of the tank.” We have always 
estimated the effect of the excentric G by the space on the edge of the tank traversed 
by the bar : the number 2*7 was entered down at once from the journal-book, whereas, 
to have suited it to the form of expression made use of, it should have been reduced 
to the centre of the polisher. 
