Show v TOUGHENED TOUGHENED I 1 GLAS GLASS j SOME particulars OF THE RECENT remarkable DISCOVERY although the manufacture of glas glass has been carried on for about 2000 years it does not appear that any attempts to overcome its in herent brittleness and liability to fracture and at the same time to preserve its transparency have proved successful afi if indeed they bave havo avei been made which I 1 is doubtful it is a true that thab the french philosopher JRe Ile aumer aulner many years since hardened glass Forne somewhat what by exposing it to a high temperature for a considerable time but bat this process which is technically termed while it hardens at the same time crystallizes the glass and renders it opaque opaque the product being known as Ream keam reamers Rc amura urs porcelain seven beven years vears since however M francois ile de la a bastie bastle a french engineer after long and patient ton into the tiie subject discovered a simple means of rendering glass practically and a at t th the same time of preserving its transparency S pa rency there were many dell delis cate conditions involved in the process by which he obtained this result hi his s success being achieved much in the same way aa as was pal ral 11 an endeavoring to repeat the successful experiment ho failed railed signally Ig nally for two years more M dola do la bastle hastle wilo posses possesses es ample means strove without avail to ta rediscover the secret of hla hia s af at length however lie succeeded in so doing and has since been en in perfecting his invention and developing a laboratory experiment peri ment into practical working the thor process of conversion conver sion slon in the main is a very simple simpie one BO so dimple that it seems seema bI bin dular gular it was never thought of or before bro broadly adly st stated at ed it consists in heat ing rig the glass at a certain ceran temperature ani awl plunging it ift while hot into toa ton a bath consisting of a heated oleaginous compounds compo there are however ninny conditions in connection lection with the tho details of the process upon which a batti satti satisfactory factory result depends and the neglect of any even in a slight degree con the difference between success and band failure thus thug the gla gia as may be ed and may not be susceptible to the enn eff deflect eat of the bath or it ii may be overheated and then it ilc will lose its shape bragain or again irmay it may bo rightly heated belted and yet be spoiled iii lil ii the bourre course of transference to the bath moreover tile the oleaginous constituents of the bath ath and their temperature have an im pa bear bearing lug lur upon the ultimate result results these and numerous other points of detail e tail tali have all been satisfactorily factor facto rily ll settled bail byrl by M delabastide de la laBastie bastie who has designed furnaces and baths by means of which his toughening process can call bo bd carried out practically iril ivil hout bout fear or br mischance the time becu occupied pied pled ia in the actual process drocea of tempering is merely nominal for directly the ai tides are re brought to the required t temper apor they ame are plunged into the bath and withdrawn the cost of te tempering too ia stated to bevi be very ery amdal we lave observed that M de do la bastie bastle wont through a long along course of experimental research r before he attained success he first worked as an engineer naturally would upon mechanical principles I 1 knowing now that the fragility of class glass results from the weakness of the bolie cohesion sion slon of its itei molecules mole moie cules culee lie he not unreasonably expected that by forcing forcin 1 thee thule te molecules more closely together and thus rendering thomass the mass more compact the strength and solidity of the material would be increased but this doctrine which holds good with iron Ironi and ind steel as sir joseph whitworth has practically demonstrated st does not bot apply 10 lo glas glass compression falling 11 to 0 toughen it even if applied to tor it when in a alula fluid or ar soft goft condition tion by applying heat only force in another another form the desired end is attained and the physical properties prop emmies effies of the material become altered in a very remarkable mauger manger manner to this singular fact we can ahn testify from the inspection of a number of toughened glass articles at the tho boffl ces icea of abel rey bros 9 Islin mincing cing clug lane the cepres representatives enta tives of M de do I 1 la a bastie bastio in england edgland lin gland giand in lie thele these articles which consist of watch glasses plate dishes and sheet glass bath colored add sod plain lain iain for neither transparency tr nor norco color is affected at all till and the ring or sound only slightly plight ly these art articles some of them boeing toeing exceedingly thin thiu were thrown indiscriminately ly across a room against ja r a w wan al V anai anal al fell spinning on the deal floora noon rW ater iter was boiled in a saucer evern ever over a n fire and the saucer eancer was quickly removed to a comparatively cold place pince and was ed by the sudden change of temperature pera ture one corner of a piece of glass lass lasa was held by shehand the hand in a gas iame hame until the corner became exceedingly cee hot but the beat heat was not communicated to the theother the tho other portion of the glass neither was it cracked from unequal expansion A cam comparative para tive experiment was then made with WWI a V pece ie c eo of ord ordinary na ry p plate I 1 at e glass and a similar piece of toughened gla gia glahn sn order to td show their respective of r resistance zo K fracture from the force of impact by a falling weight in each case tho the glass was about aboul six inches square and was placed in a frame the weight being dropped upon its center with the ordinary gia gla glass glaes es a two two iwo ounce brass weight falling on it from a 12 and 18 inches respectively did no damage but at 24 inches the klass glass was broken into several beveral fragments with a thinner pile piece cc of toughened glasa glass no impression was made by the same weight r falling al ling from heights ranging from 2 to 10 feet the weight simply rebounding from off the glass an eight ounce iron weight tried at it two and four feet respectively gave similar cebu results its upon the height being Inci increased eased to six feet however every the glass broke but here a another nother singular result was produced instead of or breaking into about a dozen dohen pieces piece as did the ordinary giar glas gia gla s it was smashed to atoms the largest fra fragments measured about haltan hattan hair half an inch in length and aud breadth and alid beso heso were easily reduced by the fingers to atoms varyl varying Dri in slie size from that of a pins point to that of a large vin pin vina pina shead head bead the jnes ancs of fractures in the frag fragments menta ments presented to the eye the appearance of irregular iaco laco work and these lines were moreover apparent to the tho touch but more palpably on one side bide of or the glass than than the other which of ot the two slats was the one that received the first impact of the blow we are not able abie to determine another peculiarity is that the edges of or the fracture are bynoe kyto by iob ioe means so sharp charp and therefore capable of causing incised wounds as are areL those of ord ordinary fury furt iury glass it would seem teem that the toughened glass posse enormous cohesive power but that if the equilibrium of the mass is disturbed at nt any oiled one point polut the uhe disturbance tur bance or disintegration instantly extends throughout the whole piece the atoms no longer possessing the power of colie cohesion slon sinn oatlie of abe practical nature mature of M de do ja a Bast bapties Ba sties leys leps unique discovery thero can beno bono be no qu question atlon what whatever eyer nor can there be any doubt of its value in the arts sciences and manufactures the applications which suggest themselves are innumerable an and above dabove and beyond the usefulness lessof of the process with regard to articles of domestic ush uso use uso come corne important considerations affecting the tho applied sciences especially in connection with eh chemical e in ic a I 1 man manufactures u fae fac and aud similar industries a material alike uninfluenced by the action of heat or acids haq has been so 80 long and so vainly coughr for inot not ibis in connection with vitriol chambers in the manufacture of sulphuric add and fur piping in chemical works sor for the present there remains one ong purpose to which toughened glass cannot beso be so easily n applied J anu and that Js is to window 9 in odd izes inai inas inasmuch m u h as it cannot be cut by a diamond i or other othet ordinary means oar our gla gia glaziers will therefore have a respite but we cannot give them lucli much hope that it will prove a long one as ex considerable promise are being conducted with Z the view of solving this probien kroblen pr moreover the glasst glass can ah be cut lo 10 the proper size before if it desirable the glass however is 6 I 1 readily ea ca graved either elther by selu neld inthe an fn the usual way or by mr tilghmans 0 ans aus elegant sandblast sand blast process itcan be oe easily polished ind it if can also hiso be cut by the wak ghetas ag for lustro lustre work and the like if only remains to congratulate 11 d la bastio on the useful and kalua nier aIer discovery he has made and to udd add idd that he is now erecting works in france to carry out in practice his Id genious ingenious p process ro cess london the tichborne madness runs so high in england that lady liady rad bad ceifie cliffe the cousin of rate kate doughty of the story has been beeri compelled to leave her residence in staffordshire in consequence 0 of tho the brutal impudence of thic thil th pomplo of the thre lovegr elates |