Royal Astronomical Society. 23 1 



ter rise from beneath the old red sandstone in the flanks of the 

 Malvern Hills, &c, as have been shown to exist on the opposite or 

 western side of the great field of old red sandstone. 



May 1 . — A paper was first read, entitled, " Notice of a Machine 

 for regulating high temperatures, invented by the late Sir James 

 Hall, Bart., F.G.S.," and drawn up by Captain Basil Hall, R.N., 

 F.G.S. &c. 



A letter was afterwards read from Mr. Telfair to Sir Alexander 

 Johnstone, V.P.R.A.S., accompanying a specimen of recent con- 

 glomerate rock, from the Island of Madagascar, containing frag- 

 ments of a tusk, and part of a molar tooth of a hippopotamus ; and 

 communicated by Roderick Impey Murchison, Esq. F.G.S. 



ROYAL ASTRONOMICAL SOCIETY. 



May 10. — The following communications were read : — 



On the Latitude and Longitude of the Cape Observatory. By 

 Mr. Henderson. 



In this paper Mr. Henderson assumes the geographical position of 

 the Cape Observatory to be 33° 56' $\ south latitude ; l h 13 ,n 56 s 

 east longitude from Greenwich ; the former being determined from 

 his own observations, and the latter from those of Mr. Fallows com- 

 pared by Mr. Henderson with the corresponding observations made 

 at European observatories. From the determination of the longitude 

 of the Cape Observatory here stated, compared with observations 

 made by Lieut. Meadows and by Capt. Owen, Mr. Henderson also 

 finds that the longitudes of the two Capes which inclose False Bay 

 may be stated as follows : — 



Cape of Good Hope 18° 29' 0" 



False Cape 18 50 30 east of Greenwich. 



" This longitude of the Cape Point," Mr. Henderson observes, 

 " differs only one mile from that given by La Caille (16° 10' east of 

 Paris — Memoirs of Academy of Sciences for 175 I, p. 425) j and it is 

 but justice to the memory of that distinguished astronomer to remark, 

 that the lapse of eighty years, and the superior means which the 

 present state of the science affords, have not been able to produce 

 any improvement in the geographical position of this part of the world, 

 as determined by him." 



Positions of Stars near the South Pole, from Observations made at 

 the Observatory at the Cape of Good Hope ; also by Mr. Henderson. 



There being no conspicuous star near the South Pole, which can 

 be observed in the day-time, even with the most powerful meridian 

 telescopes that are used in observatories, it becomes necessary, in the 

 southern hemisphere, for the purpose of determining the polar positions 

 of astronomical instruments, to have recourse to stars of less mag- 

 nitude than those which are observed for that purpose in the northern 

 hemisphere, and even to increase their number, in order that one or 

 more of them may pass the meridian at a convenient time of the night. 

 Since Mr. Henderson's arrival at the Cape Observatory, in April 1832, 

 seven circumpolar stars have been frequently observed with Dollond's 

 10-feet transit telescope, and Jones's 6-feet mural circle, for the 

 purpose of determining the positions of those instruments with regard 



