Mr。NasmythsaysthathehadanaccountfromCookehimselfofhissmallbeginnings。Hewasoriginallyashoemakerinasmallcountryvillage。Manyamanhasrisentodistinctionfromashoemaker’sseat。Bulwer，inhis’WhatwillHedowithIt？’hasdiscussedthedifferencebetweenshoemakersandtailors。“Theoneisthrownuponhisownresources，theotherworksinthecompanyofhisfellows:theonethinks，theothercommunicates。
Cookewasamanofnaturalability，andhemadethebestuseofhispowers。Opportunity，soonerorlater，comestonearlyallwhoworkandwait，andaredulypersevering。Shoemakingwasnotfoundveryproductive；andCooke，beingfairlyeducatedaswellasself-educated，openedavillageschool。Hesucceededtolerablywell。Hetaughthimselfgeometryandmathematics，anddailyapplicationmadehimmoreperfectinhisstudies。Incourseoftimeanextraordinaryambitiontookpossessionofhim:
nolessthantheconstructionofareflectingtelescopeofsixinchesdiameter。Theideawouldnotlethimrestuntilhehadaccomplishedhispurpose。Hecastandpolishedthespeculumwithgreatlabour；butjustashewasabouttofinishit，thecastingbroke！Whatwastobedone？Aboutone-fifthhadbrokenaway，butstillthereremainedalargepiece，whichheproceededtogrinddowntoaproperdiameter。Hisperseverancewasrewardedbythepossessionofa31/2inchspeculum，whichbyhisrareskillheworkedintoareflectingtelescopeofverygoodquality。
Hewas，however，somuchannoyedbythetreacherouslybrittlenatureofthespeculummetalthatheabandoneditsuse，andbetookhimselftoglass。Hefoundthatbeforehecouldmakeagoodachromatictelescopeitwasnecessarythatheshouldcalculatehiscurvesfromdatadependinguponthenatureoftheglass。Heaccordinglyproceededtostudytheopticallawsofrefraction，inwhichhisknowledgeofgeometryandmathematicsgreatlyhelpedhim。Andincourseoftime，byhisrareandexquisitemanipulativeskill，hesucceededinconstructingafour-inchrefractor，orachromatictelescope，ofadmirabledefiningpower。
Theexcellenceofhisfirstworksbecamenoisedabroad。