Mr Sadler acknowledges that Cobbett exaggerates the number of emigrants when he states it at 150,000 a year. Yet even this estimate, absurdly great as it is, would not be sufficient to explain the increase of the population of the United States on Mr Sadler's principles. He is, he tells us, "convinced that doubling in 35 years is a far more rapid duplication than ever has taken place in that country from procreation only." An increase of 20 per cent. in ten years, by procreation, would therefore be the very utmost that he would allow to be possible. We have already shown, by reference to the census of the slave population, that this doctrine is quite absurd. And, if we suppose it to be sound, we shall be driven to the conclusion that above eight hundred thousand people emigrated from Europe to the United States in a space of little more than five years. The whole increase of the white population from 1810 to 1820 was within a few hundreds of 2,000,000. If we are to attribute to procreation only 20 per cent. on the number returned by the census of 1810, we shall have about 830,000 persons to account for in some other way;--and to suppose that the emigrants who went to America between the peace of 1815 and the census of 1820, with the children who were born to them there, would make up that number, would be the height of absurdity. We could say much more; but we think it quite unnecessary at present. We have shown that Mr Sadler is careless in the collection of facts,--that he is incapable of reasoning on facts when he has collected them,--that he does not understand the simplest terms of science,--that he has enounced a proposition of which he does not know the meaning,--that the proposition which he means to enounce, and which he tries to prove, leads directly to all those consequences which he represents as impious and immoral,--and that, from the very documents to which he has himself appealed, it may be demonstrated that his theory is false. We may, perhaps, resume the subject when his next volume appears. Meanwhile, we hope that he will delay its publication until he has learned a little arithmetic, and unlearned a great deal of eloquence. ***** SADLER'S REFUTATION REFUTED. (January 1831.) "A Refutation of an Article in the Edinburgh Review (No. CII.) entitled, 'Sadler's Law of Population, and disproof of Human Superfecundity;' containing also Additional Proofs of the Principle enunciated in that Treatise, founded on the Censuses of different Countries recently published." By Michael Thomas Sadler, M.P. 8vo. London: 1830. "Before anything came out against my Essay, I was told I must prepare myself for a storm coming against it, it being resolved by some men that it was necessary that book of mine should, as it is phrased, be run down."--John Locke.