272 
expansion of the steam, and thereby causing condensation on 
the next admission of steam. Nobody disputes these require- 
ments of a good engine, and yet how few engines there are in 
which these conditions are fulfilled. The responsibility, how- 
ever, for this waste of coal lies more with the users than with 
the makers of steam engines. Old-fashioned engines are retained 
in use partly on account of the outlay involved in replacing 
them, and partly from a dread of novelties and refinements 
requiring more care and delicacy of treatment than steam engines 
commonly receive. Even in replacing old engines the repug- 
nance to any increase of first cost, and the distrust of departure 
from long-tried patterns, powerfully tend to a conservation of 
antiquated types of steam engines. As an encouragement to 
those who contemplate reforming their engine power, I may 
state what my own experience has been of the advantage of 
so doing. The engines and boilers originally applied at the 
Elswick Works, though representing a fair average of efficiency, 
were of the simple description then almost invariably used in 
factories. My firm, like others, was naturally averse to changing 
them. on account of the expense of so doing; but about two 
years ago they determined to begin the renoyation of all their 
old engines by putting down, as a first instalment, two large 
engines of the Corliss pattern to do the work previously per- 
formed by ten smaller engines, These two Corliss engines are 
now both at work. They have boilers of the best construction, 
and are fitted with various accompaniments favourable to 
economy of fuel, including Jukes’ arrangement of mechanical 
firing. One of these engines uses twenty-four tons of coal per 
week against sixty tons used by the engines it has superseded. 
The other appears to be doing equally well, but I have not the 
necessary data for making a similar comparison. Assuming the 
economy effected to be the same in both cases, the aggregate 
saving of coal amounts to seventy-two tons per week. The 
number of firemen required is also much diminished, and the 
general result is, that, notwithstanding the enormous rise which 
has taken place in the price of coal, the required steam power 
is now obtained at a less cost than before, after allowing for 
interest on the capital expended. 
Thus, then, the consumers of coal, as well for domestic use 
as for steam engines (under which two heads about two-thirds 
of our own consumption are comprised), have it in their power 
to economise their use of coal to an enormous extent, without 
any diminution of effect. In metallurgical and other manufac- 
turing processes there is also room for much saving of coal; 
but I must not extend my observations into that division of the 
subject. Speaking generally of coal consumption in all its 
branches, there can be little doubt that without carrying eco- 
nomy to ifs extreme limits, all the effects we now realise from 
coal could be attained with half the quantity we use. If a re- 
duction to that, or any approximate extent were effected, we 
should hear nothing more of scarcity or prchibitive prices for 
many years to come. 
And now as to the practicability of economising human labour 
in coal mines by the employment cf machinery. Much has 
already been done in applying machinery for the underground 
traction of coal, anda great reduction has thereby been effected 
both in men and horses; but the cutting of the coal is still 
almost exclusively performed by human labour. The service is 
a hard and dangerous one, and as it requires skill and experi- 
ence, it is not easily taken up by untrained men. In every point 
of view, therefore, there is the strongest inducement to substitute 
mechanical appliances for manual Jabour in the process of cutting 
coal. Many attempts have been made to make a machine do 
the work of a man in this kind of Jabour, but with only imper- 
fect success ; and yet the problem does not appear, upon the 
face of it, to be one of very difficult solution to persons accus- 
tomed to mechanical invention, and thoroughly acquainted with 
the conditions under which the work has to be performed. 
What is wanted, is a machine capable of cutting a groove at 
the base of the coal, so as to allow the superincumbent mass to 
be easily dislodged. The mode of cutting may be by hewing, 
by slotting, by sawing, or by scooping. The machine must 
travel along the face of the coal so as to follow up its cut. It 
should have a long face to work at, so as to avoid frequent 
stops and changes, and for this purpose the long-wall system 
of working must be adopted. The difficulty of supporting the 
NATURE 
roof may, in some cases, be an impediment to the adoption of 
the long wall system, but I believe the cases would be few in 
which this difficulty would be insuperable. 
Then, es to the power for driving the machine; that. must , 
clearly be compressed air transmitted from a steam-engine at the 
surface, as is now actually practised for the propulsion of all 
forms of these machines. Compressed air is not an economical 
medium for transmission of power, partly because the power ex- 
pended in its preliminary condensation is not recovered by cor- 
responding expansion in the exercise of its power, and partly 
because much of the force exerted in compression takes the form 
of heat, which is dissipated during the transmission of the air. 
In other respects compressed air is peculiarly adapted for con- 
veying power into a mine, because, unlike water, it requires no 
provision for its removal, and actually helps to supply the neces- 
sary ventilation. ‘This is a fair statement of the nature of the 
work to be done, and of the conditions under which it must be 
performed, Whatever difficulties there may be must be of a 
nature capable of being surmounted by mechanical skill and 
careful observation of the impediments to be overcome. Partial 
success has already been realised, and I confidently look forward — 
to a time when, to the many services which we exact from coal 
as a source of motive power, we shall add the cutting of the 
parent material from the solid beds in which it is deposited. 
But it is not alone in coal-mines that the extension of ma- 
chinery is called for. The dearth of labour is being felt in every 
department of industry, and we have to fear on the one handa 
ruinous collapse of trade, or on the other a continued rise in the 
price of all productions, threatening to neutralise the advantage 
of high wages, and impoverish persons dependent on fixed in- 
comes. The only hope that I see of escaping one or other of 
these alternatives is by increasing the use of machinery and di- 
minishing the direct employment of men. It is in the interest 
of working men, as well as of all other classes, that we should 
throw the burden of our wants as much as possible upon inani- 
mate power ; and it is a high function of mechanical science to 
relieve man from that description of labour which consists in the 
exertion of mere animal force, and leaves him more free for the 
exercise of skill which is beyond the province of machinery. 
One of the worst effects of dear coalis that it involves dear 
iron. Coal may be economised, but iron cannot, without positive 
loss. Production of every kind, as also steam navigation and 
railway transport, are essentially dependent upon the use of iron 
as well as of coal. Hence, dear iron, like dear coal, is a burden, 
both on manufacture and on commerce, and its dearness diffuses 
itself over every article which we derive either from foreign 
trade, or from home manufacture. But although the present 
high price of iron is chiefly due to the scarcity of coal, it is 
not wholly so. The dearness of labour employed in its pro- 
(Feb. 6, 1873 
duction is also telling seriously upon its cost, and the impor- — 
tance of substituting some system of mechanical puddling for 
the present laborious process is daily becoming more apparent. 
Many inventions for attaining this object have been tried, but 
no substantial success was realised, until Mr. Danks produced 
his rotating furnace in America. If Mr, Danks’ success be 
confirmed by continued trials, he will have conferred an immense 
benefit, both upon the makers and the consumers of iron, Un- 
happily for him, the general ideas embraced in his apparatus 
appear to have been suggested before, and although he has 
the great merit of having shown how the previous ideas on the 
subject can be rendered available, the patent laws do not afford 
him that protection which they so lavishly bestow upon others 
who have accomplished no practical result. Under an equitable 
and discriminative system of patents, Mr. Danks would have 
obtained a monopoly as due to the importance of his invention, 
notwithstanding the abortive attempts of others to reduce the 
same ideas to successful practice. It is to be hoped that ad- 
vantage will not be taken of Mr. Danks’ unprotected position to 
deprive him of an adequate reward. 5 
Having spoke of steam engines in reference to the great 
defects of those in most general use, it is only fair that I should 
acknowledge the great improvements which are exhibited by 
nearly all classes of those engines in their most modern forms. 
Mr. Bramwell, in his recent presidential address to the Me- 
chanical Section of the British Association at Brighton, points 
out with justice how much has recently been done to improve 
the efficiency of marine, locomotive, and agricultural engines, 
and urges the importance of carrying out toa still greater ex- 
tent the application of those principles which have already 
been productive of so much advantage. To this recommend- 
ation I may add that we must not neglect to follow up any new 
| line of improvement which the progress of discovery may present 
to us. . 
(To be continued.) 
re. 
