ut a ditch on
each shore, equidistant from the centre, and fill it with bituminous
concrete, as the foundation of a parapet or wharf to be formed of
similar materials. Within this a main sewer might be excavated, and
constructed in like manner of conglomerated gravel and sand from the
spot.

"It will of course occur that, although roads may be carried over the
entrances of the various docks by swing-bridges, yet these entrances
present obstacles to a direct line of sewers.

"To enable this difficulty to be overcome, very solid tunnels, floored
with hard pavement stones, set in bitumen, may be caused to descend in
subverted curves below the entrances of the docks, whence all matters
deposited may occasionally be removed by see-saw locomotive dredges on
wheels, worked either by mechanical power, or by the current acting
directly on the dredge."

While thus urging the importance of bitumen, and initiating many
mechanical operations which have quickly and extensively been turned to
the great advantage of society, Lord Dundonald was not unmindful of his
older inventions and the arguments by which he had long sought to
promote the naval strength of England. Of these inventions one in
particular--that of his improved steam-boilers--had been largely
adopted, and found highly beneficial during his absence from England,
and its use continued after his return. From them he hoped, and not in
vain, that good would result to the general extension of naval science.
He was cheered during the last years of his life by seeing the adoption
of many of the views on these matters which he had advocated long
before. Others have yet to be enforced.

CHAPTER XXX.

THE RUSSIAN WAR.--LORD DUNDONALD'S PROPOSALS TO EMPLOY HIS SECRET PLANS
AGAINST CRONSTADT, SEBASTOPOL, AND OTHER STRONGHOLDS.--HIS
CORRESPONDENCE THEREUPON WITH SIR JAMES GRAHAM AND LORD
PALMERSTON.--THEIR REJECTION.--LORD DUNDONALD'S APPOINTMENT AS
REAR-ADMIRAL OF THE UNITED KINGDOM.--PRINCE ALBERT'S INVITATION TO HIM
TO BECOME AN ELDER BROTHER OF THE TRINITY HOUSE.--HIS CORRESPONDENCE
WITH LORD PALMERSTON RESPECTING THE RESTITUTION OF HIS HALF-PAY.--HIS
LAST WORK.--HIS DEATH AND BURIAL.--CONCLUSION.

[1851-1860.]

When in June, 1851, he returned to England and surrendered his office as
Commander-in-Chief of the North American and West Indian squadron, the
Earl of Dundonald was in his seventy-sixth year. That he was still young
and vigoro