The cover this week shows the colossal Statue of Liberty at New York. Composed three-fifths of iron and two-fifths of copper, the statue weighs 100 tons. An enormous concrete monolith was built to act as a foundation for the pedestal on which the figure stands.
There is sometimes as much engineering skill in the designing and building of the "rides" in an amusement park as there is in a new bridge. The safety of thousands of holiday-makers depends on the careful and accurate planning of the engineer. No doubt many readers have spent a few enjoyable hours in an amusement park. It must have occurred to them that even there the engineer’s work is of great importance. This chapter is by William Baglev.
The colossal figure which stands at the entrance to New York Harbour was a gift from the people of France to the people of the United States. It is made of riveted metal sections and sixty men were occupied for ten years in building it. This chapter indicates some of the diverse tasks which the engineeer may be called upon to perform. The Statue of Liberty has a height of 151 ft 1 in and is built of metal, three-fifths iron and two-fifths copper. The work of erecting the statue and of making suitable foundations for its enormous weight was of great difficulty to the engineers. This chapter is by Harold Shepstone.
The Copper Shell of the Statue of Liberty
IN WORKSHOPS in France the copper shell of the Statue of Liberty was made in sections. Plaster moulds of the sections were made first and wooden copies of these were taken. On the wooden moulds the thin sheeting of copper was beaten into shape by mallets to form the shell of the statue. As the copper shell was only about 3/32 in thick, it had to be strengthened with iron bars.
Self-Contained Roller Plant
SELF-CONTAINED ROLLER PLANT designed to make flour for local consumption in wheat-growing areas. This unit carries out all the operations necessary for converting the grain into high-grade flour. It comprises wheat-cleaning plant, milling plant, break rolls, reduction rolls, sifter and dust collector. The plant has a capacity of 440 lb an hour.
A Canal Through a Mountain(Part 1)
For the canal between the port of Marseilles and the River Rhone a tunnel four and a half miles long was driven beneath a range of rocky heights. Now canal barges pass beneath these hills from the sea to the inland waterways of France. This chapter is by C Hamilton Ellis and is the eighth article in the series Below the Surface. It is concluded in part 30.
The story of the engineers who built the three underground railways of Glasgow and the three parallel tunnels under the harbour. This chapter is by C Hamilton Ellis and is the seventh in the series Below the Surface. The article is concluded from part 28.
The Milling of Flour
The picturesque windmills of the past have been superseded by huge modern mills. In the flour mill of to-day the wheat undergoes a number of operations in which separators, dust collectors, mellowing bins, conditioners, sifters, purifiers and other machines play their part. This is the first chapter of a new series entitled Industrial Machinery at Work. Chapters in this series will describe the work of the engineer in flour mills, sugar mills, boiler works, engine shops and the like. The first chapter carries on the story of grain from part 27. Edwin Judd describes how flour is milled. Specially designed machines carry out automatically the most involved operations in the treatment of the grain.
The Statue of Liberty
ON BEDLOE’S ISLAND, in New York Harbour, stands the famous Statue of Liberty. The statue itself is 151 ft 1 in. in total height and stands on a pedestal 89 feet high. The foundations are formed by a solid concrete monolith, 65 feet high, 91 feet square at the base and 66 ft 7 in square at the top. The statue weighs 100 tons. The cost of the statue, including pedestal and foundations, was £120,000.
Herbert Akroyd Stuart
Recognition of the genius of Herbert Akroyd Stuart, who died in 1927, is unaccountably tardy, but he it was who evolved and first put into practical form the principle of airless injection in oil engines.
In a memoir published by the Institution of Mechanical Engineers it is stated that “the achievements of Herbert Akroyd Stuart form a landmark in British engineering”. The most notable of these was his invention of the compression-ignition heavy oil engine so widely used to-day and more often than not confused with the diesel engine, which came into existence at least seven years after it.
Herbert Akroyd Stuart was the son of an engineer, Charles Stuart, who had a small works at Bletchley (Bucks). Akroyd Stuart was born in Yorkshire on January 28, 1864. He received a good general education at the Grammar School, Newbury (Berks), and a sound technical education at the City and Guilds of London College, Finsbury, a well-known centre of advanced engineering study in his day. Later he was employed in his father’s works, to the management of which he succeeded on the death of his father.
Stuart was at first employed on general work, and it is recorded that his attention was directed to the possibilities of the heavy oil engine by an accident in which he narrowly escaped severe burns. Examining some machinery for tinning steel plates he dropped some oil on to molten metal, and the resultant vapour immediately burst into flame on contact with a light he carried. The possibility of using oil vapour in an engine occurred to him and he started to experiment. This was in 1886.
The gas engine had been successfully introduced some ten years before, and Priestman Bros, of Hull, were working on an engine running on ordinary paraffin oil such as is used in domestic lamps. This engine was put on the market in 1888. But in the gas engine and in the paraffin engine the charge of gas, or oil vapour, and air drawn together into the cylinder had to be ignited from some external source, as has the petrol engine used in the ordinary motor car.
Stuart started on the principle of externally-derived ignition and tried a number of methods of effecting it, for he shared the belief (then current) that the oil vapour and the air forming the charge had to be thoroughly mixed before it was compressed by the return stroke of the piston and ignited. He had, however, a good deal of trouble from premature ignition, and finally thought of the novel plan of filling the cylinder with air alone on the first part of the suction stroke, and compressing it during the latter part, this compression causing, by a natural law, the evolution of heat.
The compressed air in the heavy oil engine is at a sufficiently high temperature towards the end of the suction stroke to ignite the charge when this is introduced into it in a fine spray. The discovery of this fact is entirely due to Herbert Akroyd Stuart. The charge is sprayed by means of a pump and ignition takes place when the piston may be said to be momentarily pausing before returning on the working stroke. The charge is thus burned when the volume of the compression space is virtually constant.
The principle was fully developed by 1890, in which year Stuart took out a patent for the engine. By the end of that year the first dozen automatically firing heavy oil engines were built. Another distinct novelty in the Akroyd Stuart engine was the adoption of a separate compression chamber united to the cylinder end by a bottle neck; and yet another, the cooling of the compression chamber by a water jacket. In 1891 Stuart granted a licence to Richard Hornsby and Sons, of Grantham (Lincs), for the manufacture of the engine which, with some modifications in design, was then known as the Hornsby-Akroyd engine.
The engine which was patented by Diesel in 1892 did not assume a really practicable form until 1897. In this engine the oil was injected not by a pump but by a jet of compressed air at a high pressure - from 1,000 lb to 1,200 lb per sq in. This involved the addition of a multi-stage air compressor which, not infrequently, gave rise to numerous troubles.
When the last of Stuart’s master patents had run out in 1906 a number of engine builders took up his “airless injection” principle and, with some differences in detail, the type has now become an important prime mover on land, at sea and in the air.
Why the true inventor has not been more widely recognized is puzzling. The late Professor William Robinson said: “It is interesting to note that Germans are now building the British airless-injection engine, and all the credit is given to Diesel. Not only so, but the Akroyd precombustion chamber with the narrow passage to give forced turbulence ... is used to-day as a new device and patented with slight modification”. This was true in 1930 and the position has not altered since that date. Moreover, Stuart’s invention of the water-cooled combustion chamber in 1892 has been generally used since the patent lapsed without acknowledgment of its origin.
Herbert Akroyd Stuart would, therefore, seem to have initiated those changes in oil engine construction which are most likely to endure, though recognition of his genius is both scant and tardy. Having emigrated to Australia in the year 1900, he died at Claremont, Western Australia, in 1927.
THE BIG WHEEL dominated the Earl’s Court Exhibitions in London before the war of 1914-18. There were forty cars suspended at the circumference of the great steel structure. The complete orbit was traversed in twenty minutes and power was supplied by two electric motors of 50 horse-power. The design was based on that of an American wheel.
The Southern Entrance to the Rove Tunnel
THE SOUTHERN OR SEAWARD ENTRANCE to the Rove Tunnel, which carries the Marseilles-Rhone Canal beneath the Nerthe Hills. A long rock dike running parallel to the shore forms a protected waterway between Marseilles Harbour and the entrance to the tunnel. The tunnel was completed in 1927 and on April 25 of that year the canal was opened by the late President Doumergue.
Glasgow Subway Tube
GLASGOW SUBWAY TUBE has an internal diameter of 11 feet. The gauge of the railway is only 4 feet. Until 1935 it was operated by cable traction but in that year Glasgow Corporation electrified the system.
Grain From Overseas
GRAIN FROM OVERSEAS for the flour mills of Great Britain is discharged at the quayside by pneumatic elevators which may be fixed or may be run on rails along the quay. Vacuum pumps in the elevators suck the grain from the ship’s hold through pipes to a large tank known as a receiver. This has a dust extractor fitted. The grain is then stored in silos until it is required for milling.
(Facing page 831)
The Milling of Flour
GROUP OF SIFTERS in a large modern flour mill. After the grain has passed through the break rolls it comprises such products, of varying sizes, as bran, flour, middlings and semolina. The sifters grade and separate these products for different subsequent treatment.
THE MACHINERY OF A MODERN FLOUR MILL is completely encased. The sifters are extracting the coarser stock before its purification.