A CANAL TO CONNECT THE SUTLEGE WITH THE JUMNA. 
miles ; the proportion of cost would hear 
nothing in comparison with the advantage 
which might be derived from so important 
an undertaking. 
Mr. Henderson recommends that the Sikh 
states through which the canal would have 
to pass, and whose revenues amount to 
above 55 lacs of rupees, should be called on 
to defray the expense of its construction ; 
being guaranteed by Government in a mo- 
derate rent, sufficient to cover the interest 
of the prime cost on an average estimate of 
the traffic after the canal had been several 
years constructed. 
We think this latter proposition is not 
likely to be carried into effect. We suggest 
to our friends at Agra, a joint stock com- 
pany, as more feasible. 
The advantages to be derived from the 
construction of the canal are innumerable. 
We need only state that this would soon 
become the route to and from Eu- 
rope. 
THE PRACTICABILITY AND PRO- 
BABLE EFFECT OF A BREAK- 
WATER AT MADRAS. 
We perceive some very important docu- 
ments in the Madras Herald of the 17th 
September on the above subject. A let- 
ter from G. Rennie, Esc[. to Capt. Grindley 
dated 3rd December, 1835, gives the 
following description of breakwaters which 
have been constructed from the earliest to 
the present time. 
The ports of Alexiindria, Tyre, and Carthage, 
were partly protected by moles, or breakwaters of 
loose stones, and in the time of the Greeks similar 
works were constructed at Ephesus, at the celebra- 
ted port of Pyrceus near Athens, at Egjna, Mytelene, 
Lemuos, Cyssus, Milo, Naxos, Eubcea, &c. ; and 
ill the time of the Uoinans, the most famous artifi- 
cial ports were Portus Lumce of Hercules fnow 
Leghorn), of Brundisi, Tarentum, of Mlseiia, Puz- 
zubli, Nisela, Ravenna, Ancona, Ostia, &c. ; of 
which the latter presented the example of an insa- 
lated breakwater in front of the harbour. In later 
times the celebrated insulated breakwater of Civi- 
ta, Vecchia, of Trani, and Barletta in Italy; and in 
more modern times the moles of Genoa, Messina, 
Rhodes, Cette, Nice, Antibes, Toulon, Valeniia, 
Barcelona, Caithagena, Cadiz, Corunna, Ferrol, 
Rochefort, the Isle of Rhe, St. Jean de Leon, and 
lastly the famous insulated breakwaters of Cher- 
bourg, Plymouth, and Delawarre— Examples are 
not wanting therefore of moles, acted upon by the 
waves, either in connected, or in insulated masses. 
The methods of construction adopted by the ancients, 
wete either by throwing large stones into tLe 
SOS 
sea, until they had formed masses of sufficient mag- 
nitude to resist the action of the waves, or by sink- 
ing masses of stones and cement held together by 
frames as described by Virtuvius, or by jetties of 
piles driven into the sea as practised at Euboea and 
elsewhere. The moderns have adopted the same 
methods according to circumstances, and there 
seems no reason to deviate from the ancient prac- 
tice, altlioiieh several plans for the formation of 
breakwateis have been proposed and practised by 
the moderns, as the masses of brick and cement 
sunk at Sheerness, by the late General Bentbam ; 
and which entirely failed, and the more absurd 
propositions of floating chests of wood, aud cast 
iron. The destruction of the cones at Cherbourg 
aud subsequently of the barracks on that Breakwa- 
ter, have taught the French several dearly-bought 
lessons. The most approved method of forming 
breakwater has been to throw large stones weighing 
from 6 to 10 tons in the line of direction of the 
proposed breakwater, aud allow them to assnme 
their natural slope, which they will do below the ac- 
tion of the waves, and the waves will perform the rest. 
But in order that these slopes may be formed it be- 
comes necessary to give such a base as shall allow 
for ihe natural slopes both below aud above water, 
and this, experience has shewn to be the caseboth 
in Cbeibourg and Plymouth Breakwaters, The 
oriainal form of the Cherbourg Breakwater was at 
prismatic figure, havingS natural slopes of 45 de 
grees and one sea slope of 8 degrees ; experience 
has, however, proved tire total inadequacy of the 
Cherbourg Breakwater as originally constructed in 
1781 after the failure of the cones, inasmuch as that 
its dimensions were too feeble to resist the impulse 
of the waves at low water, and that it afforded no 
protection to the roadsteads between high and low 
water— the magnitude of the works has been tripled 
and ill some places quadrupled since that period ; 
and when completed it expected to have its sum- 
mit raised 10 feet above high water. To have a natural 
slope of about 45<* on its interior side between 
high and low water maiks a sea slope of 5^ to one 
and from low water mark to the bottom a natural 
slope of 45* 
The Plymouih Breakwater was originally pro- 
posed to be constructed upon the triangular system, 
with its interior slope inclined to one angle of 46* 
and its exterior or sea slope at 18« or to one. 
Subsequent consideration, however, led Mr, Rennie 
to adopt an entirely new form for its section. The 
average depth of the Breakwater at Plymouth below- 
low water of an 18 feet tide is forty fee.’, but in 
some places the depth is 43 feet and in others only 
20 feet: now the breadth of the Breakwater in the 
part where it is 20 feet in depth at low water (and 
which is the depth of the water at Madras) is 350 
feet at the base, including the slopes— as it is now 
completed— the top of that patt of the Breakwater 
having been swept or flattened down towards the 
land side by the great storm of 1829. The base 
was then only 250 feet, thus pointing out the neces- 
sity or further augmentation of base and a change 
in the slopes. The actual section of the Breakwa- 
ter as now completed is shewn by the annexed 
diagram. 
i 
Mr. Rennie states that the above form 
has been found to answer most effectually 
and to remain undisturbed during the great- 
est storms. Another letter addressed to 
Capt. Cotton is of great importance, for it 
emanates from Major De Havilland, whose 
