The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1869-10-31
Modern MccIinnicnI scienco.

by an NOSifUfluS EfIQ1neer1flq MnQuzt1le, we
present several points of Interest,"
PATENTs.--The greatest illustration of the
beneficial working of the patent laws was sup
piled, In my opinion, by james Watt, when, just
about one hundred years ago, he patented his
invention of a hot-workng cylinder and sepa-
rate stcam-engine condenser After years of
contest against those adverse circumstances that
beset every important innovation, james Watt
with failing health and sCanty means, was only
upheld in his struggle by the deep conviction of
the ultimate triumph of his cause. This convc-
tion gave him confidence to enlist the co-opera-
tion of a second capitalist, after the first had
failed him, and of asking for an extension of his
declining patent. without this oppOrtune help
Watt could not have succeeded to mature his
invention; he would, in all probability, have re-
lapsed into the mere instrument-maller with
broken health and broken heart, and the inven-
ton of the steam-engine would not. only have
been retarded for a generation or two, 6ut its
final progress would have been based probably
upon the coarser conceptions of Papin, Savory,
and Newcomer.
The GREAT WORKS OF THE YEAR.-In view
ing the latest achievements of engineering sci
ence, two works strike the Imagination chiefly
by their exceeding magnitude, and by the inli-
ence they are likely to exercise upon the traffic
of the world The FIRST of these is the great
Pacific Hallway, which, in passing through vast
regions hitherto inaccessible to civilized man,
and over formidable mountain chains, Joins Cali
lornia with the Atlantic States of the great
American republic. The second is the Suez
shipping canal, which, Notwithstanding adverse
opened very shortly to the commerce of the
world. These works must greatly extend the
range OF commercial enterprise in the North
Pacific and the Indian Seas. The new waterway
to India will, owing to the difficult navigation
of the Red Sea, be in effect only available for
ships propelled by steam, and will give a stimu-
lus to that branch of engineering.
TELEGRAPHs.-Telegrap communication with
America has been rendered more secure against
interruption by the successful submersion of the
French Transatlantic Gable. On the other hand,
telegraphic communication with India still re-
mains in n very unsatisfactory condition, owing
to imperfect lines and divided administration.
To supply remedy for this public evil, the
Indo European Telegraph Company will shortly
open its special lines for Indian correspondence.
In Northern Russia, the construction of land
line is far advanced to connect St. Petersburg
with the mouth of the Amoor river, on compile
ton of which only submarine link between
the AmOOr and San francisco will be wanting
to complete the girdle round the earth. With
these great highways of speech once established,
a network of submarine and aerial wires will
soon follow. to bind all inhabited portions of our
globe together into a closer community of inter
csts, which, if followed up by steam communi-
cation by land and by sea- will open out great
and meritOTious field for the activity of the civil
and mechanical engineer.
WARFARE.-Whilc the extension of commu-
niCatiOn occupies the attention of perhaps the
greater number of our engineers, others arc en-
gagged upon weapons of offensive and defensive
warfare. We have scarcely recovered our won
der ut the terrific destruction dealt by the Arm
strong gun, the WhitwOrth bolt. or the steel
barrel consolidated under krupps gigantic
steam hammer when we hear OF a shield of
such solidity and toughness as to bid defiance
to them all. a larger Gun, or a hard bolt by
Palliscr or Gruson, is the successful answer to
this challenge, when again defensive plating,
of greater tenacity to absorb the power residing
in the shot, or of such imposing weight and
hardness combined to resist the projectilc
absolutely Causing it to be broken up by the
force residing within itselD, is brought for
ward. The ram OF war With heavy iron sides,
which few years since was thought the
most formidable, az it certainly was the most
costly weapon ever devised, is already being
superseded by vessels OF the Captain type, us
designed by Captain Coles, and ably carried out
by Laird Brothers, with turrets earned with
guns of gigantic powe0 that resist the heaviest
firing, both on account of their extraordinary
thickness and of the angular direction in which
the shot is likely to strike By an ingenious de-
vice Captain MoncreH lowers his gun upon its
rocking carriage after firing, and thereby does
away with embrasures (the weak place in pro-
tecting works., while at the same time he gains
the advantage OF reloading his gun in compara-
tive safety. 1t is presumed that in thus raising
formidable engines of offensive and defensive
warfare, the civilized nations of the earth will
pause before putting them into earnest opera
ton, but if they should do sO it is cOnsolatory
to think that they could not work them for long
without effecting the total exhaustion of their
treasures already drained to the utmost in their
construction.
REFRIGERATIoN.-Altho heat may be said
to be the moving principle by which all things
in nature are accomplished, an excess of it
is not only hurtul to some of our processes, such
as brewing, and destructive to our nutriments,
but to those living in hot climates, or sitting in
crowded rooms, an excess of temperature is fully
as great a source of discomfort excessive cold
can be. Why, then, may | ask, should we not |
resort to refrigeration in summer as well as
to calorifcation in winter, if it can be shown |
that the one can be done at nearly the same |
cost as the other? So long as we rely for
refrigeration upou our ice cellars, or upon !
importation OF ice from distant parts, we |
shall have to look upon refrigeration as costly
luxury only, but by the use of properly-con- |
structed machines it will be possible, believe. |
to produce refrigeration at an extremely |
moderate expenditure of fuel and labor. |
machine has already been constructed |
capable of producing pounds of ice or
its equivalent for ! pound of coal, where |
as the equivalent values of positive heat |
developed in the combustion of pound of coal, |
and of negative heat residing in pound of ice |
already justifes the employment of refrlgerating
machines upon large scale, but it is hard to |
say what practical results may yet be reached |
with an improved machine on strictly dynamical |
principles, because such Il machine seems not |
tied in its results to any definite limits. In
changing, for instance, pound of water from
the liquid into the gaseous state, given num-
Der of units of heat are required, that may be .
produced by combustion of coal or by the eX-
penditure of force, but in changing the same
pound of water into ice, heat is not lost, but
gained in the operation, which heat must be
traceable to another part of the machine, either
as sensible heat or as developed force. 1t would
lead me too far to enter at present into pprticu-
lars on this question, which is one not without
interest for the physicist and the mechanical