年产万吨氯化法钛白粉工程项目建议书

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1、andsolvethisproblem.Heknewthatcholerawouldneverbecontrolleduntilitscausewasfound. Hebecameinterestedintwotheoriesthatpossiblyexplainedhowcholerakilledpeople.Thefirstsuggestedthatcholeramultipliedintheair.Acloudofdangerousgasfloatedarounduntilitfounditsvictims

2、.Thesecondsuggestedthatpeopleabsorbedthisdiseaseintotheirbodieswiththeirmeals.Fromthestomachthediseasequicklyattackedthebodyandsoontheaffectedpersondied. JohnSnowsuspectedthatthesecondtheorywascorrectbutheneededevidence.SowhenanotheroutbreakhitLondonin1845,he

3、wasreadytobeginhisenquiry.Asthediseasespreadquicklythroughpoorneighborhoods,hebegantogatherinformation.Intwoparticularstreets,thecholeraoutbreakwassoseverethatmorethan500peoplediedintendays.Hewasdeterminedtofindoutwhy. Firsthemarkedonamaptheexactplaceswhereal

4、lthedeadpeoplehadlived.Thisgavehimavaluableclueaboutthecauseofthedisease.ManyofthedeathswerenearthewaterpumpinBroadStreet(especiallynumbers16,37,38and40).Healsonoticedthatsomehouses(suchas20and21BroadStreetand8and9CambridgeStreet)hadhadnodeaths.Hehadnotforese

5、enthis,sohemadefurtherinvestigations.Hediscoveredthatthesepeopleworkedinthepubat7CambridgeStreet.Theyhadbeengivenfreebeerandsohadnotdrunkthewaterfromthepump.Itseemedthatthewaterwastoblame. Next,JohnSnowlookedintothesourceofthewaterforthesetwostreets.Hefoundth

6、atitcamefromtheriverpollutedbythedirtywaterfromLondon.HeimmediatelytoldtheastonishedpeopleinBroadStreettoremovethehandlefromthepumpsothatitcouldnotbeused.Soonafterwardsthediseasesloweddown.Hehadshownthatcholerawasspreadbygermsandnotinacloudofgas. Inanotherpar

7、tofLondon,hefoundsupportingevidencefromtwootherdeathsthatwerelinkedtotheBroadStreetoutbreak.Awoman,whohadmovedawayfromBroadStreet,likedthewaterfromthepumpsomuchthatshehaditdeliveredtoherhouseeveryday.Bothsheandherdaughterdiedofcholeraafterdrinkingthewater.Wit

8、hthisextraevidenceJohnSnowwasabletoannouncewithcertaintythatpollutedwatercarriedthevirus. Topreventthisfromhappeningagain,JohnSnowsuggestedthatthesourceofallthewatersuppliesbeexamined.The