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August i, 1885.] The Australasian Scientific Magazine. 
An affluent, too, may generally be said to be smaller than its recipient, 
and may often be more correctly called a rivulet or torrent : and here 
it may be remarked that there is a great advantage in attending to the true and 
proper use of these relative terms, rivers, torrents, rivulets, streams, or brooks; 
the two latter being more or less synonymous, and a torrent being 
generally applied to a rapid mountain stream ; all these, more or less, bring 
down detritus from the hills, which is deposited at the mouths of the streams, 
or wherever other natural causes retard the rapid flow of water. In these 
cases deltas are formed, i.e., the Zambesi and Nile, which deserve exami- 
nation, and are either fluviatile, lacustrine, or marine, according as the 
river empties itself into another river, a lake, or the sea. 
But there are other important chaiacters which deserve attention in the 
description of a river; and chiefly the name is to be considered. Does it 
change during its course, and when and where ? How far up from the 
mouth is the same name preserved? and is it the same on both banks? What 
is its origin, and by whom was it first given ? Then we must enquire what 
islands are met with in its course? Where are they situated ? Are they 
low? Subject to inundation ? Marshy or rocky ? or do they stand high 
above the level of the stream? Are they cultivated or not? What are their 
natural productions ? By what animals are they inhabited ? Again, is the 
river at all affected by rapids, or shoals, or cataracts ? and what are the 
peculiar characteristics of these impediments to navigation ? Does the 
tide flow in them, and how far up is it felt? Does the river abound with 
eddies or whirlpools, and how are they occasioned ? Do they interfere 
with the navigation or not ? Are they accompanied by rocks or shoals ? 
Again, we must ascertain what fords a river offers, and what depth of 
water is generally found over them : the nature of the bed of the river, particu- 
larly in the case of a ford, should also be carefully ascertained. 
In addition to these remarks, many other important peculiarities 
will often be discovered by the careful observer. In some countries, 
particularly in secondary limestone districts, the rivers are remarkable 
for their subterranean courses. Suddenly emerging in large volumes from 
the base of a lofty mountain, they flow across rich alluvial plains, and are 
then as suddenly lost in the cavities of another mountain, again to issue 
forth to the light of day in a distant region, after their subterranean course. 
Nor should the traveller omit to notice, when crossing a river, the direction in 
which it flows as regards to his own course, whether to the right or to the 
left. Several distinguished travellers have been unable to correct their 
observations from not having sufficiently attended to this point. 
4. Springs . — The phenomena connected with the outbursts of water 
from the surface of the earth are not only of greatest interest, but a correct 
observation of them is attended with the greatest practical advantage. 
The traveller should state, approximately at least, their size or volume, 
and the nature of the rock or soil out of which they rise; also whether they 
are pure or mineral, and what deposits are found about the orificies 
through which they issue ; how they are affected by different seasons; 
whether they are of ordinary temperature or thermal, and if the latter it is 
desirable to ascertain the degree of heat by means of a thermometer ; 
the touch alone is a very vague and uncertain test. It is also desirable, 
when it can be done conveniently, to procure specimens in closely secured 
bottles, of the water of such springs as appear to possess mineral properties, 
or to contain salts in solution, for the purpose of analysis at home. 
5. Lakes . — These sheets of water, varying greatly in size, form very 
important features in the geographical description of a country, and the 
