ability to grasp them. They bewilder us, but
they fail to make a solemn impression. The genesis of the mountains
comes more within the scope of the intellect, and the majesty of the
operation is enhanced by our partial ability to conceive it. In the
falling of a rock from a mountain-head, in the shoot of an avalanche,
in the plunge of a cataract, we often see more impressive
illustrations of the power of gravity than in the motions of the
stars. When the intellect has to intervene, and calculation is
necessary to the building up of the conception, the expansion of the
feelings ceases to be proportional to the magnitude of the phenomena.

*****

I will here record a few other measurements executed on the Rosegg
glacier: the line was staked out across the trunk formed by the
junction of the Rosegg proper with the Tschierva glacier, a short
distance below the rocky promontory called Agaliogs.

Rosegg Glacier.

No. of Stake. Hourly Motion.

1 0.01 inch.

2 0.05

3 0.07

4 0.10

5 0.11

6 0.13

7 0.14

8 0.18

9 0.24

10 0.23

11 0.24

This is an extremely slowly moving glacier; the maximum motion hardly
amounts to seven inches a day. Crevasses prevented us from continuing
the line quite across the glacier.

********************

X. RECENT EXPERIMENTS ON FOG-SIGNALS.

[Footnote: A discourse delivered in the Royal Institution, March 22,
1878.]

The care of its sailors is one of the first duties of a maritime
people, and one of the sailor's greatest dangers is his proximity to
the coast at night. Hence, the idea of warning him of such proximity
by beacon-fires placed sometimes on natural eminences and sometimes on
towers built expressly for the purpose. Close to Dover Castle, for
example, stands an ancient Pharos of this description.

As our marine increased greater skill was invoked, and lamps
reinforced by parabolic reflectors poured their light upon the sea.
Several of these lamps were sometimes grouped together so as to
intensify the light, which at a little distance appeared as if it
emanated from a single source. This 'catoptric' form of apparatus is
still to some extent employed in our lighthouse-service, but for a
long time past it has been more and more displaced by the great lenses
devised by the illust