Now in the case of ( 1 ) the Merchant, what shall I see? I shall see a straight line DAE , in which the middle point ( A ) will be very bright because it is nearest to me; but on either side the line will shade away rapidly into dimness , because the sides AC and AB recede rapidly into the fog and what appear to me as the Merchant’s extremities, viz. D and E , will be very dim indeed .

On the other hand in the case of ( 2 ) the Physician, though I shall here also see a line ( D′A′E′ ) with a bright centre ( A′ ), yet it will shade away less rapidly into dimness, because the sides ( A′C′ , A′B′ ) recede less rapidly into the fog ; and what appear to me the Physician’s extremities, viz. D′ and E′ , will be not so dim as the extremities of the Merchant.