288 SCIENTIFIC RECORD FOR 1882. 



at Cambridge, who published it both in his large work, 'A Com- 

 plete System of Astronomy,' and in his elementary treatise intended 

 for the use of students in the university. We have not been able to 

 consult the earlier editions of these works to ascertain whether, as is 

 probably the case, the article was published in Maskelyne's lifetime, 

 but it is found in Vol. I of the ' System of Astronomy,' which ap- 

 peared in 1814, and is dedicated to Maskelyne, and also in the fourth 

 edition of the ' Elements of Astronomy,' Cambridge, 1816. The article 

 is entitled 'A new method of computing the effect of parallax, in 

 accelerating or retarding the time of the beginning or end of a transit 

 of Venus or Mercury over the sun's disk, by IS evil Maskelyne, D. D., 

 r. R. S., and Astronomer Eoyal.' After explaining his method and 

 how an approximate value may be corrected, as a numerical example he 

 compares the duration of the transit of Venus in 1769 as observed at 

 TTardhus and Otaheite, assuming as an approximate value of the mean 

 horizontal parallax 8".83 (nearly that found by Du Sejour), and con- 

 cludes : ' Hence the mean horizontal parallax of the sun=8".83x(l — 

 0.0121) = 8".72316.' In the 'Elements of Astronomy' there is the 

 additional sentence : ' We assume, therefore, the mean horizontal paral- 

 lax of the sun = 8|' ;■' but this does not appear in Vince's larger work, 

 nor is it quite clear whether it is an addition of M.askelyne's or his own. 

 " Lalande says the first edition of Vince's ' Elements of Astronomy' 

 was published in 1790, and Vol. I of the larger work in 1797. Probably 

 some of our readers may be able to refer to the earlier editions." 



Solar eclipses. — The British scientific expedition sent to the banks of 

 the Upper Nile to make observations of the total eclipse of the sun, 

 June 17, was every way successful. The chief members of the party 

 were Norman Lockyer, Arthur Schuster, Mr. Woods, assistant, Mr. 

 Lawrence, and Mr. Black. The special correspondent to the London 

 Daily Xcws summarizes the results as follows: 



" This eventful morning was the finest we have yet had, cool and with- 

 out a cloud. A great crowd of natives in picturesque costumes lined 

 the road and the hill between the camp and Sohag. The shore of tlie 

 Nile, except before the observatories, was packed with dahabiyehs 

 bringing the governors of the provinces and other notables to observe 

 the eclipse and do honor to the strangers. Thanks to Moktar Bey, in 

 charge of the camp, and a force of soldiery, there was no confusion. 

 Along a line of three hundred yards the French, English, and Italian 

 observers were left in undisturbed possession of tents and observatories. 

 Nevertheless, while the skj- darkened pnd assumed a leaden hue, the 

 hills bounding the Nile bathed in j^urple, the great silence gave way, 

 and from the river and i)alm-shaded slope arose a shout of wonder and 

 fear, which reached its climax at the moment of the sun's disappearance; 

 nor ceased then, for in addition to the horror of an eclipse (which the 

 •natives here in Africa attribute to the act of a dragon) there appeared 



