69 
of Edinburgh, Session 1862 - 63 . 
Vol. XII., on the True and Apparent Dip of Strata ; and there is 
a pleasing and somewhat elaborate paper in the second volume of 
the G-enevese Memoirs on the native birds of the district.* To 
these I shall merely make this general reference. But I wish to 
mention three occasional papers, somewhat original in their nature, 
and which are characteristic of the pleasure which Xecker took in 
cultivating subjects connected with Physical G-eography and Natural 
Philosophy, in an enlarged acceptation, just such as M. Saussure 
would have relished. 
The first of these was an attempt to connect in a general way 
the great lines of geological stratification over the globe, with the 
lines of equal magnetic intensity, as traced by Hansteen and 
G-eneral Sabine. This was as early as 1830,f and it is only fair 
to state, that the knowledge either of the one or of the other class 
of phenomena was then, at all events, too limited to justify any 
confident deductions on the subject. The comparison of these lines 
of direction was not, however, made without considerable research, 
and the growing interest of the inquiry, and perhaps the increasing 
probability of its having some physical foundation, induces me to 
recall attention to Necker’s memoir. The recent speculations of 
Dr Lloyd tend in the same direction, and I think also the observa- 
tions of MM. Schlagintweit. In Necker’s later writings, such as 
the preface to his Etudes^ and in his letters to Mad. Necker, we 
find that he continued to give weight to the theory of the 
connection of magnetic with geological phenomena. 
The next of these papers is contained in a letter addressed to Sir 
David Brewster, printed in the “ Philosophical Magazine” for 1832. 
It describes a very beautiful optical phenomenon observed by the 
author in the Alps, when the direct ra3^s of the sun are concealed 
by a line of forest fringing some rising ground between the spec- 
tator and the sun. The outlines of the trees, and even their 
entire stems, are then seen to shine with a white light of dazzling 
brilliancy, resembling frosted silver. The effect is not peculiar to 
* The memoir on birds seems to have been also printed separately. Xecker’s 
kinsman, M. H. de Saussure, a very competent judge, styles it “ charmante 
production devenue tres rare, trop peu connue a I’etranger, et qui meriterait 
une nouvelle edition.” Its date is 1823. 
t Bibl. Universelle, tom. xliii. 1830. 
VOL. V. 
K 
