76 The Astronomer Itoyal on the 



spheric variation, or by exercise, whether of body or mind. The 

 excellent health which the crews of the West Indian steam packets 

 have, that are in constant transition from heat to cold, is a striking 

 proof of this, and other instances of a like kind, were it necessary, 

 might be adduced in confirmation. — The Temperature of Man 

 within the Tropics. By John Davy, M.D., F.R.S. Philosophical 

 Transactions, Part II. for 1850. 



Postscript. — The thermometer with which the preceding obser- 

 vations were made was accidentally broken immediately after my 

 return to England, and in consequence I had not the means at 

 once of making further trials on temperature for the purpose of com- 

 parison. Recently, having had another thermometer constructed as 

 delicate as that before used and divided with the same minuteness 

 — each degree of Fahrenheit into ten parts — I have been enabled to 

 continue the trials ; as yet, however, only for one month, that of April, 

 without interruption. They have been made thrice daily, at about 

 the same hours as those recorded in my former paper. The results, 

 under ordinary circumstances of health, exercise, &c., have accorded 

 with those then obtained, the highest temperature having been found 

 to be immediately on rising in the morning after the night's rest, 

 and the lowest at night just before retiring to rest. This accord- 

 ance will probably be received in proof that the difference of results 

 in the West Indies and in England has been mainly owing to dif- 

 ference of climate and the habits of life connected therewith ; and 

 apart from these, to no change in the individual, the subject of the 

 trials. 



On the Total Solar Eclipse of 1851, July 28. By G. B. 

 Airy, F.RS., Astronomer Royal.* 



Mr Airy remarked that the subject vi'hich he had sug- 

 gested to the Managers of the Institution for the present 

 Lecture might at first sight appear meagre and common- 

 place, but that he believed it would be found to be one 

 of the highest interest : first, because during a total eclipse 

 we are permitted a hasty glance at some of the secrets of 

 nature which cannot be seen on any other occasion : secondly, 

 because the general phenomenon is perhaps the most awfully 

 grand which man can witness. Many of his audience had 

 probably seen large partial eclipses of the sun, and they 

 might suppose that a total eclipse is merely an intensified 



* Abstract of a Lecture delivered in the Royal Institution, May 2, 1861, 



