187 



By applying the places of the known stars in the above collection, 

 the final results are found as follows : 











a 







Sidereal 



Comet's true R. A. and 



Correction of 



3 







time at 

 Philadel- 



Dec. from Observation. 



Encke'sEphemerifl. 







Authority for 



Date. 



phia. 







"o 

 d 

 5 



Star's Place. 



ct 



<T 



Cos <f A* 



AJ* 



1842. 



h m s 



km s 



O ; // 



S. 







Mar. 27 



7 54 57 



1 46 29.54+16 44 5U.7 



+ 0.57 



+ &'a 



3 



Bessel's Zones. 



„ 27 





1 46 29.64+16 45 1.9 



+ 0.67 



+10.6 



3 



Lalande II . C. 



„ 27 



7 59 21 



1 46 30.95 +16 44 54.0 



4-1.30 



+ 0.9 



3 



Bessel's Zones. 



„ 28 



7 37 55 



1 50 5.16+16 53 44.9 



+ 2.75 



+ 2.6 



5 



>> )! 



„ 28 





1 50 4.79+16 53 51.5 



+ 2.40 



+ 9.3 



5 



Lalande H. C. 



» 31 



8 36 34 



2 1 2.83 





+ 0.33 





3 



Bessel's Zones. 



„ 31 





2 1 2.23 





— 0.24 





3 



Piazzi. 



April 11 



8 53 36 



l 30 16.67 





— 1.85 





4 



Bessel's Zones. 



h-i 



8 54 1 



2 30 17.40 





— 1.16 





4 



!> )> 



Mean of 33 results, cos <fA* = + Os.65 ± Os.32. 





19 „ Acf=+5".8 ±1".2. 





Dr. Hare laid before the Society various specimens of fused 

 iridium, osmiuret of iridium, and of rhodium. 



The largest mass of iridium weighed sixty-seven grains; that of 

 rhodium ninety grains. The former leaned towards the pale brilliant 

 white of antimony, the latter towards the ruddy hue of bismuth. Both 

 metals had a pre-eminent disposition to crystallize. The rhodium, in 

 congealing from the state of a globule as fluid as mercury, became 

 studded all over its surface with crystalline facets, excepting the por- 

 tion in contact with the support. A portion of the interior of a globule 

 of iridium ran out during congelation, coating the outside partially 

 with crystalline facets. This excessive propensity to crystallize ren- 

 dered it difficult to obtain regular globules of this metal. This pro- 

 pensity was displayed in a higher degree by the native osmiuret. Dr. 

 Hare suggested that the greater difficulty of fusing this alloy might 

 be ascribed to the infusibility of osmium, which might resemble car- 

 bon in forming a volatile oxide, and in being infusible per se. 



Dr. Hare made some remarks respecting the cause of the per- 

 sistence of clouds between certain elevated levels. 



He said that, in the last number of the Society's " Proceedings," a 

 brief mention had been made of some observations and an explana- 



