The most probable
inventor of Portland cement was Joseph Aspdin, a Leeds bricklayer, whose
obtaining of patent number BP 5022 for ‘a
super cement supporting Portland stone
being…..An improvement in the Modes of Producing an artificial stone’ was
recorded in the Leeds Mercury on 6th November, 1824. Little appears
to have been done to develop Portland stone until Joseph’s son William entered
into an agreement with a firm of Roman cement manufactures, Maude, Son & Co
of Rotherhithe in East
London to make
the Aspdin cement. There is no suggestion that the son made any innovations to
his father’s process. At this time work was underway on the building of the new
Houses of Parliament following the 1834 fire and in 1843 the contractors
carried out tests to compare Maude’s (Aspdin’s) new cement with the available
Roman cement. The results of the tests seem definitively to show that the new
cement was almost twice as strong as the finest Roman cements available. Sixty
years earlier John Smeaton called the cement he used to build the third
Eddystone lighthouse “Portland cement” because of its resemblance to Portland
stone but the evidence is far more compelling that Joseph Aspdin’s 1824 product
was indeed the first true Portland cement.
The importation
of Portland cement to North America started in the late 1860’s and was only viable because ships
crossing to load grain and cotton cargoes could carry cement as ballast free of
charge.
The development
of maintenance or ‘capital’ dredgers for such tasks as channel clearing and
land reclamation progressed separately from that of that of the aggregate
dredger by way of all manner of craft
such as the water harrow, mud mill, scrapper dredger, grab dredger, &
bucket dredger. The first hydraulic (suction) dredger using a centrifugal pump
for dredging spoil was thought to have been that invented by the M. Bazin in
1864 and it is this dredging method which was eventually adopted by the City of
York for aggregate dredging.
City of York
A paper published
in the Scientific American of 1882 records…A
new lock was constructed near Lowestoft a short time ago, and the [Bazin] dredger pump was used to empty it; when
half empty the men placed a net in front of the delivery pipe and caught a
cartload of fish, many of which where uninjured…perhaps understandably,
commercial suction dredging for fish did not follow from this event!
In the mid 1800’s
the Hampshire coast was also dredged for cement stones by cargo & fishing
vessels, which alternated between trades
as recorded at The Southampton Archives Services, to wit:-
In the 1800’s Milford-on-Sea ’s trade “.. was supplemented, to a degree by smuggling and dredging septaria
from the bay for cement making”
Friends Good Will: Built 1840. 12 tons “….1887 Coastal trade; 1888-90 Dredging cement stone at Barton Cliff,
transported to I.O.W."
Sailing vessel John
and William: Built 1846 at Oulton , Kent . 24 tons. “….1873-80 Fishing; 1889 Coastal; 1890 Dredging for cement stone at
Barton Cliff, Hurst
Castle .” It is interesting to note that at the
time that one “Arthur Payne of the Gunn
Inn, Keyhaven” was the registered owner of the John and William, the
seasonal Keyhaven salt trade “…was
supplemented, to a degree, by smuggling and dredging septaria from the bay for
cement making…”
Sailing vessel Maid
of Kent. Built 1848 at Milton , Kent . 18tons. “..1877 Fishing and stone dredging….. 1882 Laid up and dredging for
cement stone….”
Sailing vessel Mary.
Built 1844 at East
Cowes . 21
tons. “…1891 January to June dredging in Christchurch
Bay ;
July to December oyster and sprat fishing in the Solent ……1897
to 1899 Dredging in Lymington”
MARY discharging cement-stone alongside West Medina Cement Mill at Dodnor on the Isle of Wight where the septaria was turned into Medina Cement.
Alan Dinnis provided the above photograph of the Mary and writes that his grandfather was the manager of the West Medina Cement Mill which ceased production in 1944 when it became a depot for importing cement from the mainland. The mill ruins were cleared away a few years ago to become the Vestas wind turbine factory with just a few kilns remaining as an industrial archaeology site. Read more about the history of the mill in Alan's book "West Medina Cement Mill" ISBN 9 80950 4126343.
Also in 1862,
H.W.Bristow’s The Geology of the Isle of Wight . Memoirs of the Geological Survey of England and Wales , comments:- Cement stones are obtained to a small extent from Alum
Bay ,
but the greatest supply is now derived from the opposite coast of Hampshire ,
where the septaria, which once formed a portion of the Barton beds, are
procured by dredging
The method of
dredging used by these vessels is not known, be it spoon and bag, an adapted
fishing trawl, cockle scoop or some other system devised specifically for stone
dredging.?
In the early days
of ballast dredging the rights and profits from the trade belonged to the Lord
High Admiral of England but, in 1594, the privilege was
transferred by Lord Howard to Trinity House and which for many years was their
principle source of income. In the river Thames , an act of Elizabeth 1st’s reign gave the
Corporation exclusive rights to supply dredged ballast to vessels in the River
Thames from London Bridge to the sea. The trade not only provided a
useful income but also helped to keep down the river’s shoals. Trinity House
kept full rights until 1853 when the money realised from ballast was allotted
to the Mercantile Marine Fund. Trinity House craft were the chief ballast
dredgers until the Thames Conservancy, later the Port of London Authority
(P.L.A.), took over the trade.
Ballast was
needed in vast quantities by sailing colliers around the UK ’s coast and such projects as the
construction of the London Docks which used thousands of tons of dredged
material. In the mid 1800s colliers in Blyth and other North East Coast ports discharged ballast by antiquated
horse cranes before going to their loading berths. Nothing was paid for gravel
dredged from the Thames and it was unpopular with ships’ crews
who preferred to work with chalk ballast as it could be sold in the Tyne . Brigs going north to load at Blyth used to discharge as much ballast as
possible at sea before entering port as there were penalties for throwing
ballast into the river. In later years the P.L.A. supplied contractors with
most of the ballast it dredged which was carried by a fleet of battered old
craft between the dredgers in Lower Hope and ships alongside wharves at Greenwich , Leigh, Southend and elsewhere.
The removal of
sand for ballasting ships was sometimes less than welcome as exampled by the
notice given “To Owners & Masters of
Vessels” on 16th November 1863 by the Manor & Royalty of
Kenton which threatened legal action against any found removing sand from “The Warren, Warren Sands, Ridge or Pole
Sands” in Devon’s River Exe.
Dredging for Thames ballast finally stopped on 31st
March 1951
because the seams of suitable material on the bed of the Thames estuary were running out. A report at the
time confirmed that good ballast still exists in the river but only in areas
which cannot be worked by large dredgers without inconvenience to port traffic.
It was also believed that extensive dredging “..may be affecting land on the banks…”
The world wide
use of sand for ships’ ballast gave rise to the importing and exporting of all
manner of local flora such as the report which claimed “…so much ballast was coming into port, as in the case of Liverpool, it
was often used to build the foundation for new roads …hence plants from Asia,
Africa & the Americas can still be found sprouting from cracks in
undeveloped niches in the city…”. It is also reported that a number of
buildings in some of the American East Coast ports used UK sand ballast in their concrete mix.
The use of sand
for ballasting ships was generally for the duration of a voyage, stone or other
materials being used for the permanent ballast many ships carried to keep them
stable. Sand ballast needed to be properly managed on board as, whilst it
increased the stability of a ship, it could also contribute to its untimely
end, as was the case in 1880 with the 886 ton sailing ship Transit . With 60 tons of
permanent stone ballast and 352 tons of sandstone ballast “of which the master stated was more sand than stone” on board the Transit
sailed from Liverpool for Quebec on 26th September. After
leaving port, the ballast was cleared away from around the pump casings. On
October 14th the ship’s log reported “SW gale with hard squalls” and by noon she was “under lower top sails, labouring and straining heavily and making a great
deal of water” requiring the crew to be kept continually at the pumps. By noon on the 15th the pumps were
chocked with sand ballast and the crew were reduced to “bailing by bucket & tub”. At 0415hrs on October 24th
with the crew “bailing all night” the
Transit “struck the beach
of Prince Edward ’s
Island ”. “The crew all landed
safely and the Transit rapidly
filled and broke up and was eventually sold for $450”.
The subsequent
Board of Trade enquiry “did not consider
that it (the sand ballast) was proper
and safe ballast, insomuch as a large portion of it consisted of sand, and with
so much sand it should have been protected by matting or otherwise (i.e.
loaded in sacks) . For this transgression, together with a number of others
relating to the navigation of his ship, the Board of Trade suspended the
master’s certificate for three months
The River
Orwell’s River Commission established was established in 1800 and plans were
drawn up to deepen the Orwell which resulted in the purchase of a dredger which
“…. in 1920 made a cut though the Round
Ooze. Making it unnecessary for vessels to use the circuitous and difficult
channels by John’s Ness
…the following year they made a further cut to take ships straight across the
bank between Hog
Island
Reach and Limelink Reach.” The sand removed was sold “for ballast or for building” and the
money raised used to pay off the loan raised to do the work. “By 1830 The River Commissioners had paid
off the original loan of £8000 and had accumulated a surplus of £25,000, which
went towards financing the building of the wet dock”
For centuries
small wooden sailing ships came to the river Wear for coal, glass and pottery
and as they arrived on the tide and moored up, they would be served by the
keels which were flat-bottomed craft carrying a variety of buckets, skips and
slings. The ship’s crews and keelmen would unload the tons of sand ballast from
far-away beaches. As each keel was filled it made its way to the bank where the
sand would be dumped on dry land.
In the 19th
Century the sand requirements of the glassworks in Smethwick were very largely met by the particularly
pure / suitable Belgium sand which came as ballast in returning
ships employed in the export of British goods.
Another report,
from the River Tyne, records that visiting ships arriving in ballast deposited
their ballast which “commonly contained
flint and Cornish clay which could be used by local potteries” and which “buried any archaeological remains to a
considerable depth.”
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