ADDITIONAL CORRIGENDA, VOL. II. 



Page 6," line 18, omit "and clear." 



Page 50, line 18, for " Putano" read "Puntano." 



Page 55, line 8, far "eight" read "eighteen." 



ADDITIONAL CORRIGENDA, VOL. VI. 



Introduction, page xiv 



for " (A + V) = 11. 318420" read " log tang (A + V) 11. 318*20." 



For " j (A V) = 10. 216726" read " log tang (A V) = 10. 216726," and dele " tang" in two places below. 

 Page xxiv, lines three, two, and one, from bottom, should read 



<W/ = . 0000054 log. 4. 7330296 -^- = . 00005339 log 5. 7275037 



16 



= 1.0000071 l JTTTTTT; = l.ooooo7oe 



86400 86400 



- 8-64TO - - 

 Page xxv, line six, should read 



2 log 1.3648784 ^l- _ _.* log 2. 3087424 



and dele sign on pages xxiv and xxv, between the numbers and their logs. 



Page xxvn, I have said of the inclinometer : "It is a modification, by Prof. Kreil and Dr. Lloyd, of the circle devised 

 by Gauss." I was led to this by the following language in a brief notice of these instruments published, page 4 of the 

 "Supplement to the Magnelical Instructions, ffc., by Capt. C. J. B. Siddell, R. A. London, 1846." "A new dip-circle, to be used 

 with reading microscopes, has been devised by M. Gauss, and constructed, with modifications, by M. Kreil and Dr. Lloyd, 

 &c." It is stated on page xxvi of this volume that the magnetical and a portion of the meteorological instruments for the 

 expedition were made under the direction of Col. (now General) Sabine, to whose earnest interest and assistance we are 

 under the greatest obligations. This distinguished physicist informs me, Prof. Gauss never devised a dip-circle, and that 

 the only instrument used by him was made by Eobinson, with a 9-inch needle and single reading lens. The application of 

 verniers and microscopes, and the shortening of the needle permitted thereby, was a suggestion of Dr. Lloyd. Gauss never 

 saw and probably never heard of one of the latter instruments, nor did Prof. Kreil ever see one until the summer of the 

 year 1857, when a set of magnetic instruments, prepared at the request of the Austrian government, under the direction of 

 Gen. Sabine, was forwarded by the latter to Vienna. 



