Таинственный остров

           "Asthedistancefromthesticktothepoleistothedistancefromthesticktothebaseofthecliff,soistheheightofthepoletotheheightofthecliff."

           "Justso,Herbert,"repliedtheengineer;"andwhenwehavemeasuredthetwofirstdistances,knowingtheheightofthepole,weshallonlyhaveasuminproportiontodo,whichwillgiveustheheightofthecliff,andwillsaveusthetroubleofmeasuringitdirectly."

           Thetwohorizontaldistanceswerefoundoutbymeansofthepole,whoselengthabovethesandwasexactlytenfeet.

           Thefirstdistancewasfifteenfeetbetweenthestickandtheplacewherethepolewasthrustintothesand.

           Theseconddistancebetweenthestickandthebottomofthecliffwasfivehundredfeet.

           Thesemeasurementsfinished,CyrusHardingandtheladreturnedtotheChimneys.

           Theengineerthentookaflatstonewhichhehadbroughtbackfromoneofhispreviousexcursions,asortofslate,onwhichitwaseasytotracefigureswithasharpshell.Hethenprovedthefollowingproportions:—

           15:500::10:x

           500x10=5000

           500015=333.3

           Fromwhichitwasprovedthatthegranitecliffmeasured333feetinheight.

           CyrusHardingthentooktheinstrumentwhichhehadmadetheeveningbefore,thespacebetweenitstwolegsgivingtheangulardistancebetweenthestarAlphaandthehorizon.Hemeasured,veryexactly,theopeningofthisangleonacircumferencewhichhedividedinto360equalparts.