270 
NATURE 
[Fuly 22, 1886 
true that the phenomena of lake margins are closely 
paralleled by those of tide-washed coasts, but this, 
unfortunately, does not render the literature of the latter 
the more applicable, for there is a tendency to ascribe to 
the action of tides features which the students of inland 
lakes are compelled to account for independently of that 
agent. 
It should be noted also that the point of view of the 
civil engineer is somewhat different from that of the 
present study. He is, indeed, concerned with all the forms 
into which the shore material is wrought by the action of 
the waves, but he is not at all concerned with their in- 
ternal structure ; and he knows them, moreover, only as 
subaqueous banks to be determined by sounding, and not 
at all as features of the dry land. The geologic student 
has, too, some facilities for study which the engineer lacks, 
for he is frequently enabled to investigate the anatomy of 
shore structures by means of natural cross-sections, while 
the engineer is restricted to an examination of their 
superficial forms. 
Earth Shaping 
The earth owes its spheroidal form to attraction and 
rotation. It owes its great features of continent and 
ocean bed to the unequal distribution of the heterogeneous 
material of which it is composed. Many of its minor 
inequalities can be referred to the same cause, but its 
details of surface are chiefly moulded by the circulation 
of the fluids which envelop it. This shaping or moulding 
of the surface may be divided into three parts—subaérial 
shaping (land sculpture), subaqueous shaping, and littoral 
shaping. In each case the process is threefold, comprising 
erosion, transportation, and deposition. 
In subaérial or land shaping the agents of erosion are 
meteoric—rain, acting both mechanically and chemically, 
streams, and frost. The agent of transportation is 
running water. The condition of deposition is diminishing 
velocity. 
In subaqueous shaping, or the moulding of surface 
which takes place beneath lakes and oceans, currents 
constitute the agent of erosion. They constitute also the 
agent of transportation ; and the condition of deposition 
is, as before, diminishing velocity. 
In littoral shaping, or the modelling of shore features, 
waves constitute the agent of erosion. Transportation is 
performed by waves and currents acting conjointly, and 
the condition of deposition is increasing depth. 
On the land the amount of erosion vastly exceeds the 
amount of deposition. Under standing water erosion is 
either #77 or incomparably inferior in amount to deposition. 
And these two facts are correlatives, since the product of 
land erosion is chiefly deposited in lakes and oceans, and 
the sediments of lakes and oceans are derived chiefly 
from land erosion. The products of littoral erosion 
undergo division, going partly to littoral deposition and 
partly to subaqueous deposition. The material for littoral 
deposition is derived partly from littoral erosion and 
partly from land erosion. 
That is to say, the detritus worn from the land by 
meteoric agents is transported outward by streams. 
Normally it is all carried to the coast, but owing to the 
almost universal complication of erosion with local uplift, 
there is a certain share of detritus deposited upon the 
basins and lower slopes of the land. At the shore a 
second division takes place, the minor portion being 
arrested and built into various shore structures, while the 
major portion continues outward and is deposited in the 
sea or lake. The product of shore erosion is similarly 
divided. A part remains upon the shore, where it is com- 
bined with material derived from the land, and the 
remainder goes to swell the volume of subaqueous 
deposition. 
the forms of the land are given chiefly by erosion. 
Since the wear by streams keeps necessarily in advance 
of the waste of the intervening surfaces, and since, also, 
there is inequality of erosion dependent on diversity of 
texture, land forms are characterised by their variety. 
The forms of sea beds and lake beds are given by 
deposition. The great currents by which subaqueous 
sediments are distributed sweep over the ridges and other 
prominences of the surface and leave the intervening de- 
pressions comparatively currentless. Deposition, depend- 
ing on retardation of currents, takes place chiefly in the 
depressions, so that they are eventually filled and a 
monotonous uniformity is the result. 
The forms of the shore are intermediate in point of 
variety between those of the land and those of the sea 
bed ; and since they alone claim parentage in waves, they 
are su? generis. 
Ocean shores are genetically distinguished from lake 
shores by the co-operation of tides, which cannot fail to 
modify the work accomplished by waves and wind currents. 
The shores which constitute the objective basis of the 
present discussion were tideless; and the discussion is 
therefore limited to lake shores. It is perhaps to be 
regretted that the systematic treatment here proposed 
could not be extended so as to include all shores, but 
there is a certain compensation in the fact that the results 
reached in reference to lake shores have an important 
negative bearing on tidal discussions. It was long ago 
pointed out by Elie de Beaumont! and Desor® that many 
of the more important features ascribed by hydraulic 
engineers to tidal action, are produced on the shores of 
inland seas by waves alone; and the demonstration of 
wave-work pure and simple should be serviceable to the 
maritime engineer by pointing out the results in explana- 
tion of which it is unnecessary to appeal to the agency 
of tides. 
CAPILLARY ATTRACTION 
HE heaviness of matter had been known for as many 
thousand years as men and philosophers had lived 
on the earth, but none had suspected or imagined, before 
Newton’s discovery of universal gravitation, that heaviness 
is due to action at a distance between two portions of 
matter. Electrical attractions and repulsions, and mag- 
netic attractions and repulsions, had been familiar to 
naturalists and philosophers for two or three thousand 
years, Gilbert, by showing that the earth, acting as a 
great magnet, is the efficient cause of the compass 
needle’s pointing to the north, had enlarged people’s 
ideas regarding the distances at which magnets can 
exert sensible action. But neither he nor any one 
else had suggested that heaviness is the resultant of 
mutual attractions between all parts of the heavy body 
and all parts of the earth, and it had not entered the 
imagination of man to conceive that different portions of 
matter at the earth’s surface, or even the more dignified 
masses called the heavenly bodies, mutually attract one 
another. Newton did not himself give any observational 
or experimental proof of the mutual attraction between 
any two bodies, of which both are smaller than the moon. 
The smallest case of gravitational action which was in- 
cluded in the observational foundation of his theory, was 
that of the moon on the waters of the ocean, by which the 
tides are produced ; but his inductive conclusion that the 
heaviness of a piece of matter at the earth’s surface, is the 
resultant of attractions from all parts of the earth acting 
in inverse proportion to squares of distances, made it 
highly probable that pieces of matter within a few feet or 
a few inches attract one another according to the same 
law of distance, and Cavendish’s splendid experiment 
verified this conclusion. But now for our question of this 
evening. Does this attraction between any particle of 
* “Tecons de Géologie pratique,’’ Paris, 1845, v. i. p. 232. 
2 “Geology of Lake Superior Land District,’’ by Foster and Whitney, 
Washington, 1851, v. ii. pp. 262, 266. 
a 
