364 Astronomy. 



sion rarely exceeds, half a minute, why should we doubt that ce- 

 tacea, accustomed to remain submersed in their own element for 

 a period of not less than fifteen or twenty minutes, without the 

 necessity of respiration, are able to reiterate the action of suck- 

 ing and swallowing while adhering to the mother''s teat ? 



I may add, that to avoid any accidental chance of error, I 

 was assisted in these experiments by my friend Dr Gumming of 

 Chester. 



10 Albyn Place, September 18. 1834. 



Astronomy. 



The Professorship of Practical Astronomy in the Univer- 

 sity of Edinburgh, which became vacant by the death of Dr 

 Blair in the year 1828, has now been filled up by the ap- 

 pointment to that office of Thomas Henderson, Esq. lately astro- 

 nomer at the Cape of Good Hbpe : he has also the title of Astro- 

 nomer-Royal to Scotland ; and is directed by his commission to 

 carry on a series of observations in the Edinburgh Observatory 

 on the Calton Hill, expressly with a view to the improvement 

 of astronomy, geography, and navigation, the results to be re- 

 ported twice in the year to his Majesty's Government. From the 

 zeal and intelligence manifested by Mr Henderson when at the 

 Cape observatory, where he made at least 10,000 observations in 

 the course of fourteen months, and the fact, that he has obtained 

 his present appointment expressly by the recommendation of the 

 Astronomical Society of London, and eminent individual members 

 of that body, we anticipate most favourably for the reputation of 

 ourEdinburgh Observatory. Mr Henderson has an assistant,and 

 has at his command a mural circle six feet in diameter, a tran- 

 sit instrument about eight feet in length, with an object-glass 

 six and a-half inches in diameter, and an azimuth and altitude 

 circle of which the vertical circle is three feet in diameter, and 

 the azimuth circle two feet. These three instruments, the first 

 and last of which were made by Troughton and Simms, and the 

 transit instrument by Repsold of Hamburgh, (the object-glass 

 by the late Frauenhofer), are inferior to no instruments in the 

 world. 



