Plants. Plants. 1 × 50 in 1st year = 50 50 × 50 " 2nd " = 2,500 2,500 × 50 " 3rd " = 125,000 125,000 × 50 " 4th " = 6,250,000 6,250,000 × 50 " 5th " = 312,500,000 312,500,000 × 50 " 6th " = 15,625,000,000 15,625,000,000 × 50 " 7th " = 781,250,000,000 781,250,000,000 × 50 " 8th " = 39,062,500,000,000 39,062,500,000,000 × 50 " 9th " = 1,953,125,000,000,000 51,000,000 sq. miles--the dry surface} of the earth × 27,878,400--the } = sq. ft. 1,421,798,400,000,000 number of sq. ft. in 1 sq. mile } --------------------- being 531,326,600,000,000 square feet less than would be required at the end of the ninth year. You will see from this that, at the end of the first year the single plant will have produced fifty more of its kind; by the end of the second year these will have increased to 2500; and so on, in succeeding years, you get beyond even trillions; and I am not at all sure that I could tell you what the proper arithmetical denomination of the total number really is; but, at any rate, you will understand the meaning of all those noughts. Then you see that, at the bottom, I have taken the 51,000,000 of square miles, constituting the surface of the dry land; and as the number of square feet are placed under and subtracted from the number of seeds that would be produced in the ninth year, you can see at once that there would be an immense number more of plants than there would be square feet of ground for their accommodation. This is certainly quite enough to prove my point; that between the eighth and ninth year after being planted the single plant would have stocked the whole available surface of the earth.