24 
NA LORIE 
[Wov. 4, 1869 
Thus, during the Triassic epoch, extensive dry land seems 
to have existed in North America, Western and Central 
Europe, Eastern Europe, Central India, and South Africa, 
as it does now; and, throughout this vast area, the 
Dinosaurvia—the links between reptiles and birds—seem 
to have been represented by not fewer, probably by many 
more, than nine or ten distinct genera. 
I hope, shortly, to have the honour of placing the details 
of the researches into the structure and distribution of the 
Dinosauria, in which I have been engaged for the last two 
years, and of which the above notice is one of the results, 
before the Geological Society. 
T. HW. HUXLEY 
LELD IOS BIRCS IO) Mile 1, SION IRON, 
[Zhe Lditor does not hold himself responsible for opinions expressed 
by his Correspondents, | 
The Suez Canal 
Tue, all-engrossing topic of the day is the Suez Canal, about 
which some diversities of opinion still exist. As for many years back 
I have had my attention particularly drawn to some of the chief 
matters in dispute, haying been engaged on the largest irrigation 
works in India, I venture to trouble you with the following 
remarks. 
Engineering science and indomitable energy have, in the case 
of the Suez Canal, overcome difficulties which at one time 
were considered insurmountable ; but even up to the present 
moment doubts still exist, and some fear that the whole scheme 
may yet provea failure, owing to the débris of the Nile travelling 
eastward transported by the currents of air and water. That 
we can overcome the former is, inmy opinion, beyond all doubt ; 
for it is found that whenever an irrigation channel is run 
out from the Jumna Canal into the great desert of Northern 
India, rich vegetation takes the place of arid sand. And 
so in Egypt will irrigation force back the desert; so the 
only question is, Can irrigation be carried out on an extensive 
scale? And of this also I have no doubt, for the enormous 
volume of water which now flows into the sea and is lost, is quite 
sufficient to reclaim the whole of the desert. 
It may be asked, Can the water be made to flow over the 
desert? And of this I hold that there can also be no doubt. 
The very name of the Timsa Lake proves, I think, that the 
Nile, or at least a branch of it, flowed eastward, for the word 
Timsa signifies crocodile, showing that the water must at one 
time have been brackish or fresh, for these creatures could not 
have existed in this lake had it been salt as at present. If, 
therefore, a portion of the Nile water at one time flowed eastward, 
there can be no great engineering difficulty to make it do so again ; 
and I am almost inclined to think that it would have been better 
to have made the canal a fresh-water one, for it is only by vegeta- 
tion, the produce of irrigation, that the desert can be kept under 
control. Other advantages may be cited, such as cleaning the 
bottom of ships by bringing them into fresh water, and the preven- 
tion of any of the disturbed and very muddy waters along the 
Mediterranean coast getting admission into the canal; for by 
keeping the water in the canal at a higher level than that of 
the sea at both ends there could only be an outflow. So all 
the water wasted would be expended on lockage. 
It may be objected that the fresh-water canal would get silted 
up by the muddy waters of the Nile; but could not this Timsa 
Lake be used asasilt-trap? I donot mean to say, that the present 
canal will be a failure because it has not been made a fresh-water 
one ; but what I do think is, that possibly inthe end a fresh-water 
canal would have been best and perhaps cheapest, as the dredging 
of the canal might have been much reduced,* as the water could 
have been kept at a higher level in the canal. 
The great difficulty, however, to contend against, appears to 
me to be to keep a deep-water channel at the Mediterranean end 
of the Canal; and what drew my attention to this more than a 
dozen years ago, was the fact that the harbour of Alexandria does 
* I observe that, in a discussion at the Civil Engineers Institution, the 
total excavation of the Suez Canal is stated to be 70,000,000 cubic metres. 
The excayation of the Ganges Canal was 2,547,000,000 cubic feet, or a little 
over 70,000,000 metres ; but this latter does not include some 3,000 miles of 
distribution channels. 7 
not get silted up. Some have supposed that the subsidence of the 
delta accounts for this, and that the small advance of the land on 
the sea in this direction is owing to a constant sinking of the 
land. In my opinion a very different cause can be assigned : 
Nature here is working by a very different agency, namely, 
the current in the Mediterranean which flows eastward all along 
the African coast, and transports the débris of the Nile, depositing 
it all along the western portion of the Mediterranean. The 
fact of the Timsa Lake being at one time fresh or brackish, goes 
to support this view; so the only question is, Will the cost of 
continuous dredging be so excessive that the Canal will become 
a financial failure? On this point I cannot venture to give an 
opinion, as I have no data, but I think this difficulty may be 
met by forcing this easterly current to aid in keeping the mouth 
of the Canal clear of silt deposits. 
What aids this current to transport the earthy matter is the 
beat of the sea always stirring the mud and sand up on the coast, 
and enabling the water to hold a large proportion of matter im 
suspension, and even to transport heavy matter.” 
The proportion of earthy matter a short distance out to sea 
is comparatively little, so the great object appears to me to 
prevent the agitated water travelling as it does at present, and this 
can be done by arranging the breakwaters somewhat as shown 
in this diagram. 
MEDITERRA 
Cc 
PREVAILING a 
>_> 8 
CURRENT NS, 4 
NEAWN 
D 
4 ral 
CEES ol) Se ek ee eee es See 
SS = (= ——<—<—<—<—<$——$<— 
ie} 
= 
2 
j= 
Hina 
The breakwater AB is intended to prevent the very muddy 
water travelling along the coast, and the point A should extend 
well out into deep water. The breakwater CD is to direct the 
comparatively pure water where the sea is deep to pass across the 
mouth of the canal ; and by the funnel-mouthed shape thus given, 
the velocity at p will be increased, and thus keep deep water at 
the head of the canal. Some may say that the expense will be 
enormous, and that it will have to be year after year extended. 
But, in reply to this, I say that deltas do not extend out into the ~ 
sea at so rapid a rate as some suppose; and that the formation 
of a delta takes several thousands of years to accomplish, 
so that in this very delta, the advance is hardly perceptible ; 
and that a sinking of the land has been brought forward, to account 
for the very slow progress made; while, in fact, Nature has at 
present a power at work which is quite sufficient to explain the 
reason why so little advance is made on the sea during the his- 
toric period (see my paper on the Delta of the Irrawaddy, 
read before the Royal Society of Edinburgh in 1857). 
In conclusion, I haye no doubt this Suez Canal will have many 
ready to abuse it and say it is a total failure, as has been said of the 
Ganges Canal; but like the latter work, which last year saved 
some three million human beings from starvation, so will this 
canal, I have little doubt, outlive the abuse, and become one of 
the greatest blessings to the civilised world. 
T. Loin, C.E., late of the Ganges Canal. 
London, Oct. 29, 1869. 
* At Felixstowe, last March, during a gale of wind, I watched a mass ot 
brickwork, some eighteen inches square and about six inches thick, moved 
along the coast by the action of the waves, which were in an oblique direc- 
tien to the coast, and no doubt the same takes place along the mouths of the 
Nile. By a sample I took of this agitated water, I found it contained 0°7375 
per cent. of its weight of small pebbles, sand, and mud. This sample was 
taken at a hejght of nearly ten feet above the sea, and was got by catching 
the spray of the sea as it was falling. 
