ent z ▁later ▁noted ▁that ▁these ▁transformations ▁did ▁in ▁fact ▁preserve ▁the ▁form ▁of ▁Max well ' s ▁equations ▁to ▁all ▁orders ▁of ▁. ▁L arm or ▁noticed ▁on ▁that ▁occasion ▁that ▁length - cont raction ▁was ▁deriv able ▁from ▁the ▁model ; ▁further more , ▁he ▁calculated ▁some ▁manner ▁of ▁time ▁d ilation ▁for ▁electron ▁or bits . ▁L arm or ▁specified ▁his ▁consider ations ▁in ▁ 1 9 0 0 ▁and ▁ 1 9 0 4 . ▁Independ ently ▁of ▁L arm or , ▁also ▁Lor ent z ▁( 1 8 9 9 ) ▁extended ▁his ▁transformation ▁for ▁second ▁order ▁terms ▁and ▁noted ▁a ▁( math emat ical ) ▁Time ▁D ilation ▁effect ▁as ▁well . ▁ ▁Other ▁phys ic ists ▁besides ▁Lor ent z ▁and ▁L arm or ▁also ▁tried ▁to ▁develop ▁a ▁consistent ▁model ▁of ▁elect rod ynam ics . ▁For ▁example , ▁Emil ▁C ohn ▁( 1 9 0 0 , ▁ 1 9 0 1 ) ▁created ▁an ▁alternative ▁Elect rod ynam ics ▁in ▁which ▁he , ▁as ▁one ▁of ▁the ▁first , ▁disc arded ▁the ▁existence ▁of ▁the ▁a ether ▁( at ▁least ▁in ▁the ▁previous ▁form ) ▁and ▁would ▁use , ▁like ▁Ernst ▁Mach , ▁the ▁fixed ▁stars ▁as ▁a ▁reference ▁frame ▁instead . ▁Due ▁to ▁incons isten cies ▁within ▁his ▁theory , ▁like ▁different ▁light ▁spe eds ▁in ▁different ▁directions , ▁it ▁was ▁su pers eded ▁by ▁Lor ent z ' s ▁and ▁Ein stein ' s . ▁ ▁Elect romagnet ic ▁mass ▁