scientific secrets-µÚ2ÕÂ
°´¼üÅÌÉÏ·½Ïò¼ü ¡û »ò ¡ú ¿É¿ìËÙÉÏÏ·ҳ£¬°´¼üÅÌÉ쵀 Enter ¼ü¿É»Øµ½±¾ÊéĿ¼ҳ£¬°´¼üÅÌÉÏ·½Ïò¼ü ¡ü ¿É»Øµ½±¾Ò³¶¥²¿£¡
¡ª¡ª¡ª¡ªÎ´ÔĶÁÍꣿ¼ÓÈëÊéÇ©ÒѱãÏ´μÌÐøÔĶÁ£¡
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡11¡£¡¡SILVER¡¡PLATING¡¡FLUID
Dissolve¡¡one¡¡ounce¡¡of¡¡nitrate¡¡of¡¡silver£»¡¡in¡¡crystal£»¡¡in¡¡12¡¡ounces¡¡of¡¡soft¡¡
water£»¡¡then¡¡dissolve¡¡in¡¡the¡¡water¡¡two¡¡ounces¡¡of¡¡cyanuret¡¡of¡¡potash£»¡¡shake¡¡
the¡¡whole¡¡together¡¡and¡¡let¡¡it¡¡stand¡¡until¡¡it¡¡becomes¡¡clear¡£¡¡Have¡¡ready¡¡
some¡¡1/2¡¡ounce¡¡vials£»¡¡and¡¡fill¡¡them¡¡half¡¡full¡¡of¡¡whiting£»¡¡then¡¡fill¡¡up¡¡the¡¡
bottles¡¡and¡¡it¡¡is¡¡ready¡¡for¡¡use¡£¡¡The¡¡whiting¡¡does¡¡not¡¡increase¡¡the¡¡coating¡¡
powder¡¡¡¡¡it¡¡only¡¡helps¡¡to¡¡clear¡¡the¡¡articles¡¡and¡¡save¡¡the¡¡silver¡¡fluid¡¡by¡¡
half¡¡filling¡¡the¡¡bottles¡£¡¡The¡¡above¡¡quantity¡¡of¡¡materials¡¡will¡¡cost¡¡about¡¡
1¡£62c¡££»¡¡so¡¡that¡¡the¡¡fluid¡¡will¡¡be¡¡about¡¡3¡¡cents¡¡a¡¡bottle¡£¡¡It¡¡is¡¡used¡¡in¡¡
the¡¡same¡¡way¡¡as¡¡the¡¡gold¡¡plating¡¡fluid¡£
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡12¡£¡¡QUICKSILVER¡¡PLATING¡¡FLUID
Take¡¡of¡¡quicksilver¡¡one¡¡ounce£»¡¡one¡¡ounce¡¡nitric¡¡acid£»¡¡one¡¡ten¡¡cent¡¡piece£»¡¡
rain¡¡water¡¡1/2¡¡pint¡¡to¡¡a¡¡pint£»¡¡put¡¡the¡¡three¡¡first¡¡articles¡¡into¡¡a¡¡tumbler¡¡
together£»¡¡let¡¡them¡¡stand¡¡until¡¡dissolved£»¡¡occasionally¡¡stirring£»¡¡then¡¡add¡¡
the¡¡water£»¡¡and¡¡it¡¡is¡¡ready¡¡for¡¡use¡£¡¡This¡¡is¡¡used¡¡in¡¡the¡¡same¡¡way¡¡as¡¡the¡¡
silver¡¡and¡¡gold¡¡plating¡¡fluid¡£
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡13¡£¡¡TO¡¡GILD¡¡STEEL
Pour¡¡some¡¡of¡¡the¡¡ethereal¡¡solution¡¡of¡¡gold¡¡into¡¡a¡¡wine¡glass£»¡¡and¡¡dip¡¡into¡¡
it¡¡the¡¡blade¡¡of¡¡a¡¡new¡¡penknife£»¡¡lancet£»¡¡razor£»¡¡&c¡££»¡¡withdraw¡¡the¡¡
instrument¡¡and¡¡allow¡¡the¡¡ether¡¡to¡¡evaporate£»¡¡the¡¡blade¡¡will¡¡then¡¡be¡¡found¡¡
to¡¡be¡¡covered¡¡with¡¡a¡¡beautiful¡¡coat¡¡of¡¡gold£»¡¡the¡¡blade¡¡may¡¡be¡¡moistened¡¡
with¡¡a¡¡clean¡¡rag¡¡or¡¡a¡¡small¡¡piece¡¡of¡¡very¡¡dry¡¡sponge¡¡dipped¡¡into¡¡the¡¡
ether£»¡¡and¡¡the¡¡same¡¡effect¡¡will¡¡be¡¡produced¡£
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡14¡£¡¡TO¡¡GILD¡¡COPPER£»¡¡BRASS£»¡¡&c¡£¡¡¡¡¡BY¡¡AN¡¡AMALGAM
The¡¡gilding¡¡of¡¡these¡¡inferior¡¡metals¡¡and¡¡alloys¡¡of¡¡them¡¡is¡¡effected¡¡by¡¡the¡¡
assistance¡¡of¡¡mercury¡¡with¡¡which¡¡the¡¡gold¡¡is¡¡amalgamated¡£¡¡The¡¡mercury¡¡is¡¡
evaporated¡¡while¡¡the¡¡gold¡¡is¡¡fixed¡¡by¡¡the¡¡application¡¡of¡¡heat£»¡¡the¡¡whole¡¡
is¡¡then¡¡burnished¡¡of¡¡left¡¡mat¡¡in¡¡the¡¡whole¡¡or¡¡in¡¡part£»¡¡according¡¡as¡¡
required¡£
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡15¡£¡¡GILDING¡¡GLASS¡¡AND¡¡PORCELAIN
Dissolve¡¡in¡¡boiling¡¡linseed¡¡oil¡¡an¡¡equal¡¡weight¡¡either¡¡of¡¡copal¡¡or¡¡amber£»¡¡
and¡¡add¡¡as¡¡much¡¡oil¡¡of¡¡turpentine¡¡as¡¡will¡¡enable¡¡you¡¡to¡¡apply¡¡the¡¡compound¡¡
or¡¡size¡¡thus¡¡formed¡¡as¡¡thin¡¡as¡¡possible¡¡to¡¡the¡¡parts¡¡of¡¡the¡¡glass¡¡intended¡¡
to¡¡be¡¡gilt£»¡¡the¡¡glass¡¡is¡¡to¡¡be¡¡placed¡¡in¡¡a¡¡stove¡¡till¡¡it¡¡is¡¡so¡¡warm¡¡as¡¡
almost¡¡to¡¡burn¡¡the¡¡fingers¡¡when¡¡handled¡£¡¡At¡¡this¡¡temperature¡¡the¡¡size¡¡
becomes¡¡adhesive£»¡¡and¡¡a¡¡piece¡¡of¡¡leaf¡¡gold¡¡applied¡¡in¡¡the¡¡usual¡¡way¡¡will¡¡
immediately¡¡stick¡£¡¡Sweep¡¡off¡¡the¡¡superfluous¡¡portions¡¡of¡¡the¡¡leaf£»¡¡and¡¡
when¡¡quite¡¡cold¡¡it¡¡may¡¡be¡¡burnished£»¡¡taking¡¡care¡¡to¡¡interpose¡¡a¡¡piece¡¡of¡¡
india¡¡paper¡¡between¡¡the¡¡gold¡¡and¡¡the¡¡burnisher¡£¡¡It¡¡sometimes¡¡happens¡¡when¡¡
the¡¡varnish¡¡is¡¡not¡¡very¡¡good¡¡that¡¡by¡¡repeated¡¡washing¡¡the¡¡gold¡¡wears¡¡off£»¡¡
on¡¡this¡¡account¡¡the¡¡practice¡¡of¡¡burning¡¡it¡¡in¡¡is¡¡sometimes¡¡had¡¡recourse¡¡
to£»¡¡for¡¡this¡¡purpose¡¡some¡¡gold¡¡powder¡¡is¡¡ground¡¡with¡¡borax£»¡¡and¡¡in¡¡this¡¡
state¡¡applied¡¡to¡¡the¡¡clean¡¡surface¡¡of¡¡the¡¡glass¡¡by¡¡a¡¡camel¡¡hair¡¡pencil£»¡¡
when¡¡quite¡¡dry¡¡the¡¡glass¡¡is¡¡put¡¡into¡¡a¡¡stove£»¡¡heated¡¡to¡¡about¡¡the¡¡
temperature¡¡of¡¡an¡¡annealing¡¡oven£»¡¡the¡¡gum¡¡burns¡¡off£»¡¡and¡¡the¡¡borax£»¡¡by¡¡
vitrifying£»¡¡cements¡¡the¡¡gold¡¡with¡¡great¡¡firmness¡¡to¡¡the¡¡glass£»¡¡after¡¡which¡¡
it¡¡may¡¡be¡¡burnished¡£
The¡¡gilding¡¡upon¡¡porcelain¡¡is¡¡in¡¡like¡¡manner¡¡fixed¡¡by¡¡heat¡¡and¡¡the¡¡use¡¡of¡¡
borax£»¡¡and¡¡this¡¡kind¡¡of¡¡ware£»¡¡being¡¡neither¡¡transparent¡¡nor¡¡liable¡¡to¡¡
soften£»¡¡and¡¡thus¡¡to¡¡be¡¡injured¡¡in¡¡its¡¡form¡¡in¡¡a¡¡low¡¡red¡¡heat£»¡¡is¡¡free¡¡from¡¡
the¡¡risk¡¡and¡¡injury¡¡which¡¡the¡¡finer¡¡and¡¡more¡¡fusible¡¡kinds¡¡of¡¡glass¡¡are¡¡
apt¡¡to¡¡sustain¡¡from¡¡such¡¡treatment¡£¡¡Porcelain¡¡and¡¡other¡¡wares¡¡may¡¡be¡¡
platinized£»¡¡silvered£»¡¡tinned£»¡¡or¡¡bronzed£»¡¡in¡¡a¡¡similar¡¡manner¡£
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡16¡£¡¡GILDING¡¡THE¡¡EDGES¡¡OF¡¡PAPER
The¡¡edges¡¡of¡¡the¡¡leaves¡¡of¡¡books¡¡and¡¡letter¡¡paper¡¡are¡¡gilded¡¡whilst¡¡in¡¡a¡¡
horizontal¡¡position¡¡in¡¡the¡¡bookbinder's¡¡press¡¡or¡¡some¡¡arrangement¡¡of¡¡the¡¡
same¡¡nature£»¡¡by¡¡first¡¡applying¡¡a¡¡composition¡¡formed¡¡of¡¡four¡¡parts¡¡of¡¡
Armenian¡bole¡¡and¡¡one¡¡of¡¡candied¡¡sugar£»¡¡ground¡¡together¡¡with¡¡water¡¡to¡¡a¡¡
proper¡¡consistence£»¡¡and¡¡laid¡¡on¡¡by¡¡a¡¡brush¡¡with¡¡the¡¡white¡¡of¡¡an¡¡egg¡£¡¡This¡¡
coating£»¡¡when¡¡nearly¡¡dry¡¡is¡¡smoothed¡¡be¡¡the¡¡burnisher£»¡¡it¡¡is¡¡then¡¡slightly¡¡
moistened¡¡by¡¡a¡¡sponge¡¡dipped¡¡in¡¡clean¡¡water¡¡and¡¡squeezed¡¡in¡¡the¡¡hand£»¡¡the¡¡
gold¡¡leaf¡¡is¡¡now¡¡taken¡¡up¡¡on¡¡a¡¡piece¡¡of¡¡cotton¡¡from¡¡the¡¡leathern¡¡cushion¡¡
and¡¡applied¡¡on¡¡the¡¡moistened¡¡surface£»¡¡when¡¡dry¡¡it¡¡is¡¡to¡¡be¡¡burnished¡¡by¡¡
rubbing¡¡the¡¡burnisher¡¡over¡¡it¡¡repeatedly¡¡from¡¡end¡¡to¡¡end£»¡¡taking¡¡care¡¡not¡¡
to¡¡wound¡¡the¡¡surface¡¡by¡¡the¡¡point¡£
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡17¡£¡¡PROFESSOR¡¡WORTS'¡¡AMALGAM¡¡FOR¡¡SILVERING
This¡¡is¡¡the¡¡only¡¡means¡¡yet¡¡discovered¡¡for¡¡silvering¡¡iron¡¡directly£»¡¡yet¡¡it¡¡
is¡¡not¡¡so¡¡lasting¡¡as¡¡some¡¡of¡¡the¡¡other¡¡processes¡£¡¡Take¡¡quicksilver¡¡and¡¡the¡¡
metal¡¡potassium£»¡¡equal¡¡parts¡¡by¡¡volume£»¡¡put¡¡them¡¡together¡¡in¡¡a¡¡tumbler£»¡¡
and¡¡if¡¡both¡¡metals¡¡be¡¡good¡¡there¡¡will¡¡be¡¡a¡¡brisk¡¡ebullition£»¡¡which¡¡
continues¡¡until¡¡an¡¡amalgam¡¡of¡¡the¡¡two¡¡is¡¡formed£»¡¡then¡¡add¡¡as¡¡much¡¡
quicksilver¡¡as¡¡there¡¡is¡¡of¡¡the¡¡amalgam£»¡¡let¡¡it¡¡work¡¡till¡¡thoroughly¡¡mixed£»¡¡
and¡¡it¡¡is¡¡ready¡¡for¡¡use¡£¡¡This¡¡amalgam¡¡you¡¡may¡¡apply¡¡with¡¡a¡¡cloth¡¡to¡¡any¡¡
metal£»¡¡even¡¡iron£»¡¡though¡¡it¡¡be¡¡a¡¡rusty¡¡bar£»¡¡and¡¡you¡¡have¡¡it¡¡neatly¡¡
silvered¡¡over¡£
18¡£¡¡FOR¡¡COPPERING¡¡IRON
This¡¡is¡¡the¡¡latest¡¡method£»¡¡and¡¡that¡¡now¡¡in¡¡use¡£¡¡To¡¡a¡¡solution¡¡of¡¡sulphate¡¡
of¡¡copper£»¡¡add¡¡a¡¡solution¡¡of¡¡ferrocyanide¡¡of¡¡pottasium£»¡¡so¡¡long¡¡as¡¡a¡¡
precipitate¡¡continues¡¡to¡¡be¡¡formed¡£¡¡This¡¡is¡¡allowed¡¡to¡¡settle£»¡¡and¡¡the¡¡
clear¡¡liquor¡¡being¡¡decanted¡¡the¡¡vessel¡¡is¡¡filled¡¡with¡¡water£»¡¡and¡¡when¡¡the¡¡
precipitate¡¡settles¡¡the¡¡liquor¡¡is¡¡again¡¡decanted£»¡¡and¡¡continue¡¡to¡¡repeat¡¡
these¡¡washings¡¡until¡¡the¡¡sulphate¡¡of¡¡potash¡¡is¡¡washed¡¡quite¡¡out£»¡¡this¡¡is¡¡
known¡¡by¡¡adding¡¡a¡¡little¡¡chloride¡¡of¡¡barium¡¡to¡¡a¡¡small¡¡quantity¡¡of¡¡the¡¡
washings£»¡¡and¡¡when¡¡there¡¡is¡¡no¡¡white¡¡precipitate¡¡formed¡¡by¡¡the¡¡test£»¡¡the¡¡
precipitate¡¡is¡¡sufficiently¡¡washed¡£¡¡A¡¡solution¡¡of¡¡cyanide¡¡of¡¡potassium¡¡is¡¡
now¡¡added¡¡to¡¡this¡¡precipitate¡¡until¡¡it¡¡is¡¡dissolved£»¡¡during¡¡which¡¡process¡¡
the¡¡solution¡¡becomes¡¡warm¡¡by¡¡the¡¡chemical¡¡re¡action¡¡which¡¡takes¡¡place¡£¡¡The¡¡
solution¡¡is¡¡filtered£»¡¡and¡¡allowed¡¡to¡¡repose¡¡all¡¡night¡£¡¡If¡¡the¡¡solution¡¡of¡¡
cyanide¡¡of¡¡potassium¡¡that¡¡is¡¡used¡¡is¡¡strong£»¡¡the¡¡greater¡¡portion¡¡of¡¡the¡¡
ferrocyanide¡¡of¡¡potassium¡¡crystalises¡¡in¡¡the¡¡solution£»¡¡and¡¡may¡¡be¡¡
collected¡¡and¡¡preserved¡¡for¡¡use¡¡again¡£¡¡If¡¡the¡¡solution¡¡of¡¡cyanide¡¡of¡¡
potassium¡¡used¡¡to¡¡dissolve¡¡the¡¡precipitate¡¡is¡¡dilute£»¡¡it¡¡will¡¡be¡¡necessary¡¡
to¡¡condense¡¡the¡¡liquor¡¡by¡¡evaporation¡¡to¡¡obtain¡¡the¡¡yellow¡¡prussiate¡¡in¡¡
crystals¡£¡¡The¡¡remaining¡¡solution¡¡is¡¡the¡¡coppering¡¡solution£»¡¡should¡¡it¡¡not¡¡
be¡¡convenient¡¡to¡¡separate¡¡the¡¡yellow¡¡prussiate¡¡by¡¡crystallization£»¡¡the¡¡
presence¡¡of¡¡that¡¡salt¡¡in¡¡the¡¡solution¡¡does¡¡not¡¡deteriorate¡¡it¡¡nor¡¡
interfere¡¡with¡¡its¡¡power¡¡of¡¡depositing¡¡copper¡£
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡19¡£¡¡PECULIARITIES¡¡IN¡¡WORKING¡¡CYANIDE¡¡OF¡¡COPPER¡¡SOLUTION
The¡¡true¡¡composition¡¡of¡¡the¡¡salts¡¡thus¡¡formed¡¡by¡¡copper¡¡and¡¡cyanide¡¡of¡¡
potassium¡¡has¡¡not¡¡yet¡¡been¡¡determined£»¡¡but¡¡their¡¡relations¡¡to¡¡the¡¡battery¡¡
and¡¡electrolyzation¡¡are¡¡peculiar¡£¡¡The¡¡solution¡¡must¡¡be¡¡worked¡¡at¡¡a¡¡heat¡¡
not¡¡less¡¡than¡¡from¡¡150~¡¡to¡¡200~¡¡Farenheit¡¡£¨that¡¡is¡¡not¡¡quite¡¡as¡¡hot¡¡a¡¡
boiling¡¡water£»¡¡which¡¡is¡¡212~¡¡Farenheit¡££©¡¡All¡¡other¡¡solutions¡¡we¡¡have¡¡tried¡¡
follow¡¡the¡¡laws£»¡¡that¡¡if¡¡the¡¡electricity¡¡is¡¡so¡¡strong¡¡as¡¡to¡¡cause¡¡gas¡¡to¡¡
be¡¡evolved¡¡at¡¡the¡¡electrode£»¡¡the¡¡metal¡¡will¡¡be¡¡deposited¡¡in¡¡a¡¡sandy¡¡or¡¡
powdered¡¡state£»¡¡but¡¡the¡¡solution¡¡of¡¡cyanide¡¡of¡¡copper¡¡and¡¡potassium¡¡is¡¡an¡¡
exception¡¡to¡¡these¡¡laws£»¡¡as¡¡there¡¡is¡¡no¡¡reguline¡¡deposit¡¡obtained¡¡unless¡¡
gas¡¡is¡¡freely¡¡evolved¡¡from¡¡the¡¡surface¡¡of¡¡the¡¡article¡¡upon¡¡which¡¡the¡¡
deposit¡¡is¡¡taking¡¡place¡£¡¡As¡¡this¡¡solution¡¡is¡¡used¡¡hot£»¡¡a¡¡considerable¡¡
evaporation¡¡takes¡¡place£»¡¡which¡¡requires¡¡that¡¡additions¡¡be¡¡made¡¡to¡¡the¡¡
solution¡¡from¡¡time¡¡to¡¡time¡£¡¡If¡¡water¡¡alone¡¡be¡¡used¡¡for¡¡this¡¡purpose¡¡it¡¡
will¡¡precipitate¡¡a¡¡great¡¡quantity¡¡of¡¡the¡¡copper¡¡as¡¡a¡¡white¡¡powder£»¡¡but¡¡
this¡¡is¡¡prevented¡¡by¡¡dissolving¡¡a¡¡little¡¡cyanide¡¡of¡¡potassium¡¡in¡¡the¡¡water¡¡
at¡¡the¡¡rate¡¡of¡¡4¡¡ounces¡¡to¡¡the¡¡gallon¡£¡¡The¡¡vessels¡¡used¡¡in¡¡factories¡¡for¡¡
this¡¡solution¡¡are¡¡generally¡¡of¡¡copper£»¡¡which¡¡are¡¡heated¡¡over¡¡a¡¡flue¡¡or¡¡in¡¡
a¡¡sand¡bath£»¡¡the¡¡vessel¡¡itself¡¡serving¡¡as¡¡the¡¡positive¡¡electrode¡¡of¡¡the¡¡
battery£»¡¡but¡¡any¡¡vessel¡¡will¡¡suit¡¡if¡¡a¡¡copper¡¡electrode¡¡is¡¡employed¡¡when¡¡
the¡¡vessel¡¡is¡¡not¡¡of¡¡copper¡£
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡20¡£¡¡PREPARATION¡¡OF¡¡IRON¡¡FOR¡¡COATING¡¡WITH¡¡COPPER
When¡¡it¡¡is¡¡required¡¡to¡¡cover¡¡an¡¡iron¡¡article¡¡with¡¡copper£»¡¡it¡¡is¡¡first¡¡
steeped¡¡in¡¡hot¡¡caustic¡¡potash¡¡or¡¡soda¡¡to¡¡remove¡¡any¡¡grease¡¡or¡¡oil¡£¡¡Being¡¡
washed¡¡from¡¡that¡¡it¡¡is¡¡placed¡¡for¡¡a¡¡short¡¡time¡¡in¡¡diluted¡¡sulphuric¡¡acid£»¡¡
consisting¡¡of¡¡about¡¡one¡¡part¡¡acid¡¡to¡¡16¡¡parts¡¡of¡¡water£»¡¡which¡¡removes¡¡any¡¡
oxide¡¡that¡¡may¡¡exist¡£¡¡It¡¡is¡¡then¡¡washed¡¡in¡¡water¡¡and¡¡scoured¡¡with¡¡sand¡¡
till¡¡the¡¡surface¡¡is¡¡perfectly¡¡clean£»¡¡and¡¡finally¡¡attached¡¡to¡¡the¡¡battery¡¡
and¡¡immersed¡¡in¡¡the¡¡cyanide¡¡solution¡£¡¡All¡¡this¡¡must¡¡be¡¡done¡¡with¡¡despatch¡¡
so¡¡as¡¡to¡¡prevent¡¡the¡¡iron¡¡combining¡¡with¡¡oxygen¡£¡¡An¡¡immersion¡¡of¡¡five¡¡
minutes¡¡duration¡¡in¡¡the¡¡cyanide¡¡solution¡¡is¡¡sufficient¡¡to¡¡deposit¡¡upon¡¡the¡¡
iron¡¡a¡¡film¡¡of¡¡copper£»¡¡but¡¡it¡¡is¡¡necessary¡¡to¡¡the¡¡complete¡¡protection¡¡of¡¡
the¡¡iron¡¡that¡¡it¡¡should¡¡have¡¡a¡¡considerably¡¡thick¡¡coating£»¡¡and¡¡as¡¡the¡¡
cyanide¡¡process¡¡is¡¡expensive£»¡¡it¡¡is¡¡preferable¡¡when¡¡the¡¡iron¡¡has¡¡received¡¡
a¡¡film¡¡of¡¡copper¡¡by¡¡the¡¡cyanide¡¡solution£»¡¡to¡¡take¡¡it¡¡out£»¡¡wash¡¡it¡¡in¡¡
water£»¡¡and¡¡attach¡¡to¡¡it¡¡a¡¡simple¡¡cell¡¡or¡¡weak¡¡battery£»¡¡and¡¡put¡¡it¡¡into¡¡a¡¡
solution¡¡of¡¡sulphate¡¡of¡¡copper¡£¡¡If¡¡there¡¡is¡¡any¡¡part¡¡not¡¡sufficiently¡¡
covered¡¡with¡¡copper¡¡by¡¡the¡¡cyanide¡¡solution£»¡¡the¡¡sulphate¡¡will¡¡make¡¡these¡¡
parts¡¡of¡¡a¡¡dark¡¡colour£»¡¡which¡¡a¡¡touch¡¡of¡¡the¡¡finger¡¡will¡¡remove¡£¡¡When¡¡such¡¡
is¡¡the¡¡case£»¡¡the¡¡article¡¡must¡¡be¡¡taken¡¡out£»¡¡scoured£»¡¡and¡¡put¡¡again¡¡into¡¡
the¡¡cyanide¡¡solution¡¡till¡¡perfectly¡¡covered¡£¡¡A¡¡little¡¡practice¡¡will¡¡render¡¡
this¡¡very¡¡easy¡£¡¡The¡¡sulphate¡¡solution¡¡for¡¡covering¡¡iron¡¡should¡¡be¡¡prepared¡¡
by¡¡adding¡¡it¡¡by¡¡degrees¡¡a¡¡little¡¡caustic¡¡potash£»¡¡so¡¡long¡¡as¡¡the¡¡
precipitate¡¡formed¡¡is¡¡re¡dissolved¡£¡¡This¡¡neutralizes¡¡a¡¡great¡¡portion¡¡of¡¡
the¡¡sulphuric¡¡acid£»¡¡and¡¡thus¡¡the¡¡iron¡¡is¡¡not¡¡so¡¡readily¡¡acted¡¡upon¡£¡¡When¡¡
the¡¡iron¡¡is¡¡thus¡¡coppered£»¡¡proceed¡¡to¡¡silver¡¡it¡¡in¡¡the¡¡manner¡¡recommended¡¡
for¡¡silvering¡¡according¡¡to¡¡receipt¡¡No¡£9£»¡¡or¡¡if¡¡you¡¡want¡¡to¡¡put¡¡a¡¡very¡¡
heavy¡¡coating¡¡of¡¡silver¡¡on¡¡it£»¡¡make¡¡use¡¡of¡¡a¡¡strong¡¡battery¡£
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡21¡£¡¡SOLDERING¡¡FLUID
For¡¡mending¡¡articles¡¡of¡¡tin£»¡¡iron£»¡¡zinc£»¡¡copper£»¡¡and¡¡almost¡¡all¡¡other¡¡
metals¡£¡¡Take¡¡2¡¡fl¡£¡¡ounces¡¡of¡¡muriatic¡¡acid£»¡¡add¡¡zinc¡¡till¡¡bubbles¡¡cease¡¡to¡¡
rise£»¡¡add¡¡1/2¡¡a¡¡teaspoonful¡¡of¡¡sal¡¡ammoniac¡¡and¡¡2¡¡ounces¡¡of¡¡water¡£¡¡Damp¡¡
the¡¡part¡¡you¡¡wish¡¡to¡¡solder¡¡with¡¡this¡¡fluid£»¡¡lay¡¡on¡¡a¡¡small¡¡piece¡¡of¡¡lead£»¡¡
and¡¡with¡¡a¡¡piece¡¡of¡¡hot¡¡iron¡¡or¡¡soldering¡¡iron¡¡solder¡¡the¡¡part¡£
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡22¡£¡¡SOLDER¡¡FOR¡¡TIN
Take¡¡of¡¡pewter¡¡4¡¡parts£»¡¡tin¡¡1¡¡part£»¡¡bismuth¡¡1¡¡part£»¡¡melt¡¡them¡¡together¡£¡¡
Resin¡¡is¡¡used¡¡with¡¡this¡¡solder¡£
23¡£¡¡COLD¡¡METHOD¡¡OF¡¡SILVERING¡¡IRON¡¡WITH¡¡SILVER¡PLATE
Polish¡¡the¡¡iron¡¡toy¡¡wish¡¡to¡¡silver£»¡¡then¡¡damp¡¡it¡¡over¡¡with¡¡soldering¡¡fluid¡¡
£¨receipt¡¡No¡£21£©¡¡When¡¡this¡¡is¡¡done¡¡give¡¡it¡¡a¡¡coat¡¡of¡¡No¡£22¡¡solder¡£¡¡This¡¡is¡¡
done¡¡by¡¡laying¡¡a¡¡piece¡¡of¡¡cold¡¡solder¡¡on¡¡the¡¡iron£»¡¡and¡¡spreading¡¡it¡¡over¡¡
with¡¡a¡¡heated¡¡soldering¡¡iron£»¡¡when¡¡by¡¡this¡¡means¡¡you¡¡get¡¡the¡¡iron¡¡nicely¡¡
plated¡¡with¡¡solder£»¡¡then¡¡lay¡¡on¡¡your¡¡silver¡plate¡¡evenly£»¡¡and¡¡gently¡¡rub¡¡
it¡¡over¡¡with¡¡the¡¡heated¡¡soldering¡¡iron£»¡¡and¡¡it¡¡will¡¡become¡¡firmly¡¡united¡¡
with¡¡the¡¡solder¡¡as¡¡the¡¡solder¡¡is¡¡with¡¡the¡¡iron£»¡¡s