文本内容:
The historyof the cameraToday I11talk aboutthe inventionof thecamera andphotography.The camerais oftenthoughtto bea moderninvention,but asearly as1727,a Germanphysicist(物理学家)discovered thatlight darkenssilver salt(银盐).Used asa camera,a bigbox wasset up,and asmall holewas cutin oneside tolet thelight in;he madetemporary(临时的)pictureson thesilver salt.Silver saltis stillthe baseof thephotographic film(胶片)today.Then aFrench scientistnamed Josephmade thefirst permanent(永久的)picture byusinga specialpiece ofmetal(金属)which wascovered withsilver salt.A photohe madein1827still exists(存在).The painterDe Gearimproved theprocess bycovering themetal alsowith placingthemon saltwhich wecan eat.This wasin1839,the officialdate of the beginningof photography.But theproblem wasthe printingofthephotos.And itwasn tuntil otherscientists developedthekind ofphotographic paperwe usenow thatgood printswere possibleand photographybecametruly modern.In the1870s,Matthew Bradywas ableto takehis famouspictures inAmericanCivil War(美国内战).In the1920s,Dr EdwardLane inventedthe socalled〃Instant Camerawhich usesselfdeveloping film.If wesay photographycame intobeing in1839,it followsthat ittook morethan100years forthecamerato reachits presentcondition.。