TRANSACTIONS OF SECTION G. 641 
been sent to Sydney, to make sewers through the sandstone. Colonel Beaumont 
and Captain English have invented a machine which effects the same object in a 
somewhat different manner. This machine has been employed in cutting driftways 
in the chalk at the rate of about a yard an hour, both in France and in England, 
and is employed under my direction in cutting a seven-foot heading in the red 
sandstone for the Mersey tunnel, with considerable advantage. These machines 
bore the heading, and clear away and load the spoil into waggons, at one operation, 
and they enable the engineer to dispense entirely with the use of explosives. By 
this means the surrounding stratum remains intact, no more disturbance taking 
place than would follow the driving of an auger through a deal board. They are 
moved by any available power according to the situation; in the cases I have 
mentioned they have been driven by compressed air, which, as well as driving the 
machine, effects the ventilation of the heading in which the machine works. 
Tn the construction of railways and docks, one of the most expensive and tedious 
operations is the excavation of the soil. In England, the cutting of numerous canals 
had trained a large body of men to special fitness for the execution of such work, 
which they performed with a manual dexterity and amount of muscular power 
which have made the British navvy a special force in the execution of great public 
works. Where labour was comparatively scarce and inefficient, as, for instance, in 
America, efforts were made at an early period to supplement, and, if possible, super- 
sede, such manual labour by mechanical contrivances, In 1845 a mechanical ex- 
cayator, after an American model, was used on the Kastern Counties Railway with 
a certain amount of success. This machine delivered as much as 100 cubic yards 
an hour at a cost which did not exceed fifty shillmgs a day. In principle, end 
generally in detail, it is very much the same as the excavator which is commonly 
lmown as the ‘steam-navvy ’ at the present day. The machine was locomotive, and 
had three other kinds of motion—first, thrusting the scoop or shovel into the earth; 
second, lifting the scoop when filled ; and third, turning round on its centre to deposit 
the earth in the waggons. At that time thirteen of these machines were in use in 
the United States; but they have not superseded manual labour in making cuttings 
and embankments there, and they have been little used here until recently, and 
even now they only compete successfully with bone and muscle under special cir- 
cumstances. It is found economical to employ the ‘ steam-navvy ’ where there is a 
large quantity of hard and heavy clay or alluvial soil to excavate, and where the 
machine will not only effect a gross saving per day, but nearly pay for its cost in 
the course of a single contract. The disadvantages of the machine are that it is 
costly, very heavy to move, requires special plant to work with it, is not readily 
saleable when the work is finished, and costs a good deal to keep in repair. On the’ 
other hand, it will work night and day without trouble, it renders the contractor 
independent of a large amount of hand-labour, and it will work readily in soil with 
which it is extremely difficult for manual labour to deal. It is much to be desired 
that the human frame should be relieved of the exhausting labour which makes man 
a mere beast of burden, and leaves him at the end of his work only fit to lie down 
to sleep off the effects of his toil, and to regain’strength to continue the same round 
of labour on the morrow. The use of small locomotives for tipping the soil for 
embankments has relieved the workmen of one very laborious, and sometimes 
dangerous occupation, and, in a corresponding degree, has diminished the cost of 
construction. 
In the construction of a railway or dock, a large amount of pile-driving is 
frequently necessary, and the manner of sinking piles has been much considered by 
engineers, for the purpose of obtaining rapidity and economy in executing their 
works, For some purposes, where piles were formerly used, cylinders are now 
sunk, and the manner of sinking them and their form and material have been 
much studied. For fine sands, such as were met with in piling for the Morecambe 
Bay viaducts, and the promenade pier in this town, I used a disc-pile, lowered into 
the sand by its own weight, as fast as the sand was removed from under the disc 
by a jet of water forced through a tube opening at the foot of the pile—a plan which 
has been applied by others elsewhere, and notably at Calais harbour-works recently, 
where a considerable saving has been effected by its use in sinking piles for the repair 
1883. TT 
