Class I.]
METAL TUBES—FUSING CRUCIBLES—SPUN LEAD, &c.
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obtained, with these cliches, delicate vignettes, whichwould seem difficult to imitate, and some of which havealready been used for bank cheques and letters of exchange.
They have succeeded at Neiderbronn in giving greatsoftness, tenacity, and flexibility to their cast-iron, andMessrs. Dietrich have exhibited a sheet of this material,measuring 7 feet by 2| inches thick, which is veryflexible. The exhibitors consider that, for some purposesat least, these plates of cast-iron might be substituted forsheet-iron.
Gandillot and Company, Rue Bellefond, No. 49,Paris (230, p. 118.) Hollow iron and tubes.
The objects exhibited by Messrs. Gandillot consist oftwo distinct sets; the one of tubes called light tubes, in-tended for such purposes of construction, furniture, &c.,as do not require that the joints should be close; aud theother of tubes properly so called, of which the joints,being carefully soldered, are capable of resisting a pres-sure of at least .fifteen atmospheres, and are intended forheating purposes, for conveying gas, or for worms forchemical works.
These tubes are manufactured in two different ways,according to the purposes for which they are intended,and the pressure they are to bear. The common kinds,which have to resist a pressure of only fifteen to twenty-five atmospheres, are united at a white heat, beiug weldedby juxtaposition in a series of three to five decreasingdraw-plates. The degree of resistance of the weld inthese tubes depends on their greater or less thickness.
For purposes requiring a much higher pressure, M.Gandillot makes double tubes, and these he designates“ without joint.” To make these, he provides two com-mon tubes, such that one will just enter the other withfriction. The smaller is then inserted into the larger,the welds being opposite, and in this state he has themdrawn out at welding heat, and through a series ofdecreasing gauges, until the diameter of the externaltube has become smaller than that of the one originallyincluded, so that the latter is welded, and, in some mea-sure, incorporated with the other, the two togethermaking a single tube, which is then without joint.
When a punch is forcibly introduced into a tube thusmade, it tears it in some part of the circumference, butnot in the direction of the welding of the external tube;and if the trial is repeated in different portions of thesame tube, which has been previously sawn into severalparts for the purpose, at each trial the tear will com-mence in a different part, so that the measure of resist-ance possessed by such a tube is that of a piece of ironof equal thickness.
MM. Gandillot have added to their collection of ob-jects exhibited, fragments of tubes that have been tested,and these show that in fact the tearing does take placein various directions. For some purposes, especially forthe roasting of animal black, where the vapour requiresto be very intensely heated, these tubes, described as“ without joint,” have perfectly succeeded. MM. Gan-dillot have, therefore, rendered service to industry bythus providing tubes capable of bearing considerablepressure, and the Jury have, accordingly, granted thema Prize Medal.
Messrs. Groult and Company, Paris (531, p. 1204).These exhibitors manufacture brass tubing of all sizes,from l-24th of an inch to 6 inches (0 m *001 to 0 m, 150) indiameter, the thickness being so graduated that all thesizes can be placed one within the next above it. Theyalso exhibit tubes for cotton printing, for telegraphicuses, and for locomotives.
The Jury have remarked with interest, amongst theproducts exhibited by Messrs. Groult, bent tubes ob-tained by these ingenious manufacturers, by a combinationof the ordinary work of tube-drawing, with a regularrotation given to the principal tool used in the operation.These tubes tear less readily than jointed tubes, aud arebeginning to be used for conveying gas, under the nameof il rope tubes” A Prize Medal is awarded to Messrs.Groult and Co.
M. Deyeux, of Liancourt (Oise ) (476, p. 1200). Cru-cibles for fusing metals. The crucibles manufactured byM. Deyeux are of two distinct kiuds, according to the
uses for which they are destined; those intended forfusing bronze, copper, gold, and silver, are marked withthe letters [A.D.]; the others, manufactured expressly forthe fusion of cast-iron or steel, are marked No. 28.
These crucibles have been in use for the last ten years,and certificates forwarded with the objects exhibited, andsigned by the Baron Thenard, and Messrs. Barruel,Darcet, and Desprets, testify to their good quality. TheJury, who have not been able to satisfy themselves byexperiment, have been happy to take for the guidanceof their judgment in the matter, the opinion of men solearned and so competent to decide, and have accordinglygranted a Prize Medal to M. Deyeux.
Poulet, J. F., Paris (1680, p. 1257), manufacturerof spun lead. The happy idea of employing spun lead,or lead wire, for horticultural purposes, suggested itselfto Mr. Poulet, the resistance offered by this metal toatmospheric influences rendering it in most cases veryvaluable for binding and tying up vegetable substances.Among the objects exhibited we notice especially somewire of considerable tenacity, whose diameter is onlyabout ^th of an inch. The Jury have granted a PrizeMedal to M. Poulet.
Derville and Co., Paris (162, p. 1181). Marbles.The quarrying of marbles, which formerly' prosperedin France, especially under the reigns of Louis XIV. andXV., has been much neglected from the commencementof the present century, Italy within that period havingalmost exclusively supplied the statuary marble, whileBelgium furnished the greater quantity of the marblesused in France for the decoration of private houses.For some years past, however, there have been resumed,under the influence of Government, a considerable num-ber of neglected marble quarries, especially in thePyrenees and the Vosges .
The exhibition of Messrs. Derville is more particularlydirected to illustrate the marbles from the Pyrenees , theircollection including upwards of 100 slabs, 16 inches high,and offering at least 20 varieties, among which may benoticed those called Campan marbles, the marble called“griotte” (spotted with red and brown), and the whitemarble of St. Beat; all remarkable for the variety of theircolours, and the beauty of their polish. The Campanmarbles also possess a peculiar geological interest in thenumber of goniatites which they enclose, and which areoften mixed confusedly with the paste; an arrangementwhich evidences the great amouut of change which theselimestones have undergone at some period, aud whichsupports the theory of metamorphism. The Jury, takinginto consideration the different circumstances abovealluded to, have awarded a Prize Medal to Messrs,Derville'.
J. R. Colin, Marble-dealer at Epinal (1564, p. 1251),The marbles of the Vosges , to the treatment of whichtins exhibitor has especially devoted himself, take a finepolish, but their colours are less agreeable than those ofthe Pyrenees . M. Colin has also worked the granites,syenites, porphyries, and diorites, of which there is agreat variety in the Vosges ; and it is principally thesefine rocks that have attracted the attention of the Jury,and have induced them to give M. Colin a Prize Medal.Among the rocks of this kind, so difficult from theirhardness to cut and polish, the Jury have remarked a fineslab of granite with large pink crystals of felspar, theslab measuring 8 feet 2 inches long and 18 inches wide,having an extremely fine polish, but unfortunately crackedin the journey.
Messrs. Gueuvin Bouchon and Co. Millstones ofLa Ferte-sous-Jouarre (532, p. 1204). The millstonerock of La Ferte' is a silicious rock, full of interstices,presenting a multitude of empty spaces and hard por-tions, giving it a superiority over all other materialsfor the manufacture of millstones, and especially overgranites and sandstones, as the grain, being caught in thelittle cavities of the fixed stone, is immediately reducedto powder by that which revolves. The hardness of thisquartzy grinding material is such that no part of thestone becomes mixed with the grain, and this quality hasobtained for the stones in question a preference over allothers used for grinding, so that they have become a