Worcester daily spy. [volume] (Worcester [Mass.]) 1850-1888, 1871-05-01
From the Hartford Post.
GLASS Cutting by a New Process


One of the most marked triumphs of mechan-
ica skill and inventive genius is that of produc-
ing great results at what at first sight appear TO
be the most incompetent agents, and 10 utiiiz-
| ing the commonest materials to produce surpris-
ing results. One of the most remarkable in
stances that illustrate this statement is related
in The Journal of the Franklin Institute. 1t is
the plan of Mr.. B. c. Tilghman of Philadelphia
Tor cutting, carving or engraving glass and the
hardest stone by means of jet of quartz sand
thrown violently against the service by means
OF steam or other power. Mr.. Tilghman, with
a jet OF common white or quartz sand thrown
violently against block of solid corundum,
bored hole through it one and one-half inches
in diameter, one and one-half deep, in twenty
five minutes, and this with velocity obtainable
by the use of steam as propelling power, at a
pressure of three hundred pounds per square
inch-a remarkable result, when we consider
that corundum is next to and but little inferi-
or to the diamond in hardness. AT a meet
ing of the Franklin institute, held February
18th, 1871, the resident secretary, DR.. w.
H. Wahl, introduced this invention, illustrating
his description of It by practically cutting de-
polishing the surface of plate of glass by
sand blast of very moderate intensity. Various
examples of hard substances cut, depolished,
and carved into shape, were displayed In the
discussion which followed the presentation of
this very remarkable discovery, Mr. Robert
Briggs, in his interesting remarks on the sub
ject, took occasion 10 say that it had long been
wind-driven sand, near the seashore, soon loses
its polish, and cited some other well-known ex
amples of the erosion of surface when expose
to a continued stream of moving particles This
is seen on grand scale on our western plaius,
| where masses of stone, standing like monu-
ments above the surface, have been cut and
| carved into The most groiesque forms and their
surfaces finely polished by the sand being driven
against them by the force of the wind. These
singular freaks of the action of natural forces are
an in hn nj no
ment exploring expedition for a survey of the
Pacific railroad. The apparatus used by Mr.
Illghman is very simple, consisting of a COM
mon rotary fan with tube through which the
sand is driven by the air blast and if the tube is
flexible the shower may be directed as desired,
or a fixed tube may be employed and the ma
| terial TO be wrought carried back and forth or
| in vertical plane as desired. In the machine
| in use for this purpose the spent sand is recon
veyed to the upper hopper by elevators, and the
| dust made by the sand blast (Which otherwise
| might be a source of annoyance to the work
men, is drawn back into the fan, and thence
| passes with the wind INFO the blast, and again
| mingles with the shower of sand upon the glass.
| By covering parts of the glass surface by stem
Gil or pattern of any tough or elastic material,
such as paper, lace caoutchoue, or oil paint, de-
| signs of any kind may be engraved. There is
| kind of colored glass made by having a thin
| stratum of colored glass melted or FLASHED on
one side of an ordinary sheet of clear glass. If
VI uOuSllllCSS JIG pldCSu INC
colored side and exposed TO the sand blast the
pattern can be cut through the colored stratum in
| from about four to twenty minutes, according
| to thickness.
By graduating the time of exposure with suff1-
| Gent nicely, so as to allow the thin parts of
| leaves to be partly cut through by the sand,
while the thicker central ribs and their branches
still resist, the effect of a shaded engraving of
ferns may be produced. The grinding of such a
hard substance as glass by an agent which is
Inv oh q toriul
leaf, seems at first rather singular The proba-
BILE explanation is, that each grain of sand
which strikes with its sharp angle on the glass,
puverizes an infnitesimal portion, which is
blown away as DUST while the grains which
strike the leaf rebound from its soft elastic sur
face. One curious fact connected with its use
is, that when a surface, to be cut in intaglio or
otherwise is partially protected by templates of
metal, these templates curl up under the blows
of the sand, so that paper patterns are really
| more durable than patterns cut from brass.
Sheet steel, cut into shape and then hardened,
will also curl up under the blows of the fine
particles of sand, unless protected by sheets of
| yielding material. Fine lace will protect glass
during the depolishing process, and leave its de-
signs IN polished linesion ground surface.
THE SUPPLIES FOR FRANCE.-The condition
of things in France has thrown unexpected OBJ
stacles in the way of distributing the relief
funds supplied by foreign charity. In the case
Of the American contributions of provisions for
the French peasantry, it was found necessary to
abandon the intention of sending them direct to
France. The United States Storeship Supply
Commander Dewey, having on board the San
Francisco and New York provisions, and bound
for Havre, has arrived in the Thames. The Wor-
cester, with the Massachusetts gifts, has been
intercepted in the channel and now lies at Ply
mouth. Both vessels have thus escaped the
smallpox, now raging among the ships in
Havre, but of course it was not the smallpox
that drove them away. Mr.. Charles Laner of
New York, who came over here at his own ex-
pense to look after the cargo of the Supply, was
in Paris at the outbreak of the instruction. At
ter many attempts to carry out the plan of the
donors, he found it impracticable. There is no
longer any means Of transporting provisions
from HaYre or any other port in the north of
France, over either ofthe lines of railway feed
ing the districts in which relief is needed. In
fact no freight trains are running on any of the
roads, and no trains at all on any road except
the northern, which the Prussians, who are still
at St. Denis, refused to allow the communists to
stop. In these circumstances Mr.. Lanier
came to London, and afte: consultation by
cable with his committee in New York, re-
solved to sell the cargo of the Supply,
and distribute the proceeds in money among the
people whom the donors intended to reach and
who can now be reached in no other wav. He
took counsel also of the London committee of
the American funds, Mr.. Moran, now charge
d'ataires of the United States, Mr. Russell Stur-
CHS of Barring Brothers & Co, Mr.. j. S. Morgan,
and Mr.. McCulloch, formerly secretary of the
treasury in the United States, now the manager
in London of the banking house of Jay Cooke,
McCulloch & Co There are surely no gentle.
men better qualified than these four to advise
on such matter, and their opinion was unani.
nous that the only course to carry out the
wishes of the subscribers was to sell and apply
the money as Mr.. Lanier proposed. They were
unanimous, also, in thinking London the best
market for such articles, and they will them
selves undertake the apportionment of the pro-
ceeds of the cargo The Supply begins dis
charging into lighters to-day. Mr.. Lanier has
made all needful arrangements for the sale, and
will go home this week. Some fears ha re been
expressed, l am told lest there should be
feeling Of disappointment among the American
subscribers, who designed their generous gifts to
be distributed as they were given. But after
talking the matter over with several Of the gen.
tlemen above named, | have no doubt that their
decision is the wisest, and indeed the only one
that, as matters now stand, could be taken.
London correspondence NeW York Tribune.
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