42 MASSACHUSETTS AGRICULTURE. 



land upon its surface. This would be equivalent to six hundred 

 and forty persons to the square mile, a density of population 

 more than sixty per cent, greater than that of Belgium, which 

 is now the most tliickly peopled country in the world. Deducting 

 then from the 50,000,000 square miles which compose the land 

 surface of the globe, the liberal allowance of one-fifth, for 

 deserts, inland waters, mountain steeps, ice-bound regions, 

 and lands otherwise not susceptible of cultivation, we have 

 40,000,000 square miles remaining, which would support, on 

 the above assumption, 25,600,000,000 inhabitants, or just 

 twenty times the estimated population of the world at the present 

 time. This would give to the United States more than 

 1,500,000,000 inhabitants. 



These numbers may seem amazing, and the supposition of 

 such future populousness incredible. But let us consider the 

 ratio in which the human race is actually increasing on the 

 earth, and we shall see no reason to doubt that its growing 

 population will fully keep pace with its utmost possible fruitful- 

 ness. Assuming that only 6,000 years ago, (and it is, in fact, 

 considerably less,) there were but two human beings in this 

 world, how many times has the number doubled itself, in the 

 elapse of those 6,000 years ? Less than thirty times. This 

 is equivalent to doubling once in every 200 years. If the present 

 population were doubled but five times, it would greatly exceed 

 the vast number which we have estimated as the possible limit 

 of the earth's capacity to support human life. That is to say, 

 at this rate of increase, in less than 1,000 years from the 

 present time there will be 30,000,000,000 human mouths for 

 the earth to feed. But our calculation is at fault. We have 

 overlooked that great destruction of mankind, which took place, 

 according to the common reckoning, more than 1,600 years 

 after men began to multiply on the earth. Beginning then 

 with the flood, there were eight human beings on the earth 

 forty-four centuries ago. Double this number twenty-six times 

 and you have more than the earth's present population. This 

 would be doubling once in about 170 years, and would allow 

 less than eight centuries for the earth to arrive at that extreme 

 density of ))opulation which we have assumed as the limit of 

 its capacity to furnish food for man. 



