148 PROCEEDINGS OP TUE AMERICAN ACADEMY 



Ls. Lewis, Note on the Zodiacal Light. (Am. Journal of Science 



for December, 1880, Vol. CXX. pp. 437-445.) 

 M. Miiller, Photometrische Untersuchungcn. (Publicationen des 



Astrophysikalischen Observatoriums zu Potsdam. Nr. 12. 



Potsdam, 1883.) 

 *S. Schmidt, Das Zodiacallicht. Braunschweig, 1856. 

 Sp. Serpieri, La Luce Zodiacale studiata nelle Osservazioni di G. 



Jones. (Memorie della Societa degli Spettroscopisti Italian!. 



Appendice al Volume V., Anno 1876, pp. 49-161.) 

 T. Observations de la Lumiere Zodiacale h Toulouse. Notes de M. 



Gruey. (Comptes Rendus des Seances de 1' Academic des 



Sciences, Tom. LXXIX. pp. 1250-1253; Tom. LXXX. pp. 



903-906.) 

 W. "Wolf, Description du Groupe des Pleiades. (Annales de TOb- 



servatoire de Paris. Memoires, Tom. XIV. Deuxieme Partie. 



Pp. A. 1 — A. 81.) 



Tables X. to XXXIV. inclusive, in the Appendix following the 

 present discussion, exhibit the data obtained from the works by Jones, 

 Heis, and Schmidt, which are marked with asterisks in the list above. 

 Besides his own observations, Heis reports others by Weber, Eylert, 

 and Neumayer. Notwithstanding the small number of observations by 

 Eylert and Neumayer, the geographical positions at which they were 

 taken make them at least interesting, if not very conclusive. It may 

 appear superfluous to print the results of the separate observations, as 

 is done in Tables X., XL, and XII. But while some readers may be 

 dissatisfied with the subsequent course taken in the reductions, they 

 may still be able to make use of the separate observations, as here 

 arranged upon a uniform system for each observer. I have myself 

 had occasion to regret that Serpieri was prevented by want of space 

 (Sp. 61) from publishing the numerical tables by which he had repre- 

 sented all the observations of Jones. 



It has also seemed desirable to include in the Appendix a few tables 

 and a small chart intended to facilitate approximate determinations of 

 the position of the zodiacal light in the visible hemisphere. To make 

 Buch determinations with accuracy seems needless in our present state 

 of knowledge with regard to the zodiacal light, especially as the time 

 of the observations is often given without much precision. The 

 Appendix contains a description of all the tables included in it, which 

 will make it unnecessary to consider them further in this place. I 

 may accordingly pass at once to the conclusions which they suggest 

 to me. 



