Useful Discoveries

Porcelain, which has been known to the Chinese and Japaneae for ages, was not nade In Europa untU the beginttlngof the List century, when r Germán discovered the art purely accidentally. Thisman was au apprentice to an apothecary at Berlín, when be nut with au al hemist who, In return for gomegood offices done blm by lus raasler, promised to leach bim the art of Maklnggold. To discover the grand secret he labored incessanüy; and ao it happeued that, having mixed various eartha together In order to make strong cruclbles, fn the counse of baking thein lie acoldentally discovered the art of making porcelain. The Intended transmutatlon took place- not in the metala, indeed, hut in hls owb pterson- and, as if he liad been touehed witli a conjuror'.s v.aud, lie was all of a Midden ttanformedfrotnan alchemist Into a potter. The lust porcelain thog maiinlaetured was of a brownish-ied color, being made of brown elay. The power of lenses, as applled to telescopes, opera-glasses and the likt-, was diseovered by a watelnnakcr's apprenttce. Whlle holding tpectacle glasses betwen liis thumb and flngerhe wasstartled by the sudcfenly-enlarged appearance of a nelghborlng church splre. The swaylng to and tro ol a obandelier in a cathedral auggeeted to Qalileo the ïpplicatlon of the penduluiu. Me.zotinto. a particular tnethod of line engraviug on copper, o-wed its Invention to the Minple acriiieiii of the gun-barrel of a sentry DOCOmingrusted with dew. The art of lithographlng wae perfected through suggestion.s made by accident. A poor mur sieian was auxioug to know whcllier music coirtd not be etelied iipon gtone as well as copper. Af terne had prepared hia slab hi mother asked hiin to nmke a ïntmorandimi of Buch clothea as site propesed to send away to be washi'd. Noiriavlng pen, ink and paper eonvenient, he wrole the list on the stone witli theetculng preparaüon, Intending to make a OOpy of t at leisure. A lew da.vs later, when aliont to eicaii tlie stone. he wondered what effect aquafortis would have upon it. Ile applled tlie acid, and in a few minutes s:iv '" ""' ut : ¦¦¦¦m leiiel. I he next step neoes-ary was to ink the Stone and take off the inipression. Theartof etcblngupoo glasa was dise-overed by a glass-cutter accidentally letting a few drops of aquafortla fall upiin hit spectncles, Ile notloed that theglaM beeame eorroded and softened where tnc acid had touehed it, and that was hint enougli. Be drew figures apon thegiass with arni.-li, appHed the torrodlnjf fluid and then ent a.vay the glasa aroun.l the drawlngs. When the varnieh was removed the figures appared ralsed on a dark grouncl. The shop of a tobaeeonist was destroyed by tire. VVliile lie was _'ainir dolcfnlly into tlie sinoldeniij.' milis, he nolieed thal hls poorer Beighbon were gatberlng snnll' Irom the eanislers. I Ie tisled the smillliiniselt. and disrovend tliat tire liad Ilirgely nereased ils punjEWl'cy and aroma. Jt w as a hint wortli proflting by. Ile secured another shop, built a lot of ovens. ïubjected the snntr to a hetiting proefles, ave the brand a peculiar name, and in a feMl yeais lire. mie rich through an : Ident which he had at Hrst thoilght had eompU'tely rnined hiin. Tlie coruposition of which prlnting rollers are made was discovrred by a giniTDkiiaeciUnu A printer, not beingaWe tojfiiid the pelt hall usrd in times to ink the type with, substftuted a plece of gofl glue which bad tallen out ot a glae-pot It was sneh an excellent subètltute that, after' mixing inolasses wit li the glue to 'jive the nia.-s proper eonsistency, the old pelt ball wasenlirely oUcArded. Water tabbies, eniploj ", in the manufacture (¦! waed and watered Blik, were mvented by a man who got his Brei idea from tlie spreadiïig ol a squirl of