CORRESPONDENCE, 1836-4G. 149 



2. Because Baily's last printed work is the set of revised 1844. 

 boundary lines for constellations which appears on them. 



3. Because Malby is a very spirited fellow. A man proposed 

 a feasible way of mounting the globe so as to adjust it for any 

 era, giving in fact the pole of the equator a motion round the 

 pole of the ecliptic. Malby immediately set to work, got the 

 globe made with an additional contrivance for solar apogee, and I 

 have a specimen now in my hands. They are soon to be adver- 

 tised. If I were your mortal enemy I should like nothing better 

 than to dispute with you about heliacal risings, &c., of 3,000 

 years ago. How I should grin to think that you were at your 

 spherical trigonometry while I was getting within more accuracy 

 than an heliacal rising is good for, by two or three motions of the 

 hand, and a squint or two along wooden horizons and brazen 

 meridians ! 



Malby has also a very neat planisphere with one revolving 

 surface and one fixed, and on bringing the hour of the day 

 on the edge of the revolving surface to the day of the month 

 on the edge of the fixed, the hollow part of the revolving 

 surface shows the visible heavens for that hour and day. 

 These planispheres usually have three surfaces and two adjust- 

 ments. 



But whether I shall in a month or two claim your kind offer 

 about Dunlop's nebuloe depends upon Malby 's decision about the 

 whole scheme. I shall recommend him to defer ifc altogether 

 till your work appears. What can Dunlop have been at ? 

 Your optical power must have been incomparably greater than 

 his. 



Are there any atmospheric minutiaB which last long enough 

 for a careless observer, who never looks for a thing a second 

 time, to note as nebulae ? 



Banqiio. The air hath bubbles as the water hath, 



And these are of them whither are they vanished ? 



Macbeth. Into the air, and what seemed nebula; melted 



As breath into the wind ; would they had stayed ! 



No more at present from 



Yours very truly, 



A. DE MORGAN. 



