▁He ▁had ▁begun ▁developing ▁his ▁first ▁dig ging ▁machine ▁in ▁ 1 8 7 2 , ▁specifically ▁for ▁working ▁in ▁hop fields , ▁which ▁are ▁difficult ▁to ▁cultiv ate ▁due ▁to ▁the ▁inc idence ▁of ▁the ▁hop ▁pol es ▁which ▁support ▁the ▁strings ▁up ▁which ▁the ▁plants ▁clim b . ▁" Dig ging ▁by ▁Ste am " ▁by ▁Col in ▁Ty ler ▁( pub lished ▁in ▁ 1 9 7 7 ▁by ▁Arg us ▁Books ▁Ltd ) ▁dev otes ▁a ▁chapter ▁to ▁hop ▁dig ging ▁machines , ▁many ▁of ▁which ▁were ▁designed ▁and ▁built ▁by ▁Knight , ▁and ▁which ▁are ▁illustrated ▁with ▁draw ings ▁or ▁photos . ▁ ▁Other ▁invent ions ▁ ▁His ▁other ▁invent ions ▁included ▁- ▁▁ ▁Knight ' s ▁Th erm os ote ▁He at ▁S aving ▁Rad i ator , ▁for ▁which ▁pat ents ▁were ▁applied ▁for ; ▁ ▁a ▁brick ▁lay ing ▁machine ; ▁a ▁wall ▁that ▁it ▁built ▁still ▁stands ▁at ▁Bar field ▁School ▁in ▁Run fold , ▁but ▁the ▁machine ' s ▁main ▁f law ▁was ▁an ▁in ability ▁to ▁turn / build ▁corners . ▁ ▁a ▁gr en ade ▁thro wer , ▁ ▁a ▁speed ometer , ▁▁ ▁wooden ▁vehicle ▁ty res , ▁ ▁Knight ' s ▁pat ent ▁' d ish ▁lever ' ▁for ▁til ting ▁pl ates ▁when ▁car ving ▁meat . ▁ ▁Phot ography ▁ ▁He ▁was ▁a ▁keen ▁photograph er ▁and ▁pione er ▁of ▁early ▁colour ▁phot ography , ▁photograph ing ▁F arn ham ▁and ▁the ▁surrounding ▁coun tr ys ide