Mr. Thornton long ago gave proof of his competency to the treatment of some of the most important questions of practical political economy, by two works of great merit, "Over Population and its Remedy," (1)(1. London: Longman, Brown, Green, and Longmans, 1846.) and "A Plea for Peasant Proprietors." (2)(2. London: Murray, 1848.) Of the latter of these especially it may be said, that nothing but the total absence, at the time of its publication, of any general interest in its subject, can account for its not having achieved a high repute and a wide circulation. The lack of interest in the subject has now ceased; opinion is rapidly advancing in the direction which the author fayours; and a new edition, with its facts brought down to the latest date, would be welcomed by advanced politicians, and would materially contribute to the formation of an enlightened judgment on one of the economical questions on which truth is most important, and prejudice still most rife.

The present work, though popular and attractive in style, is strictly scientific in its principles and reasonings; and is therefore, as might be expected, strictly impartial in its judgments. A considerable part of the volume is employed in refuting the principles on which it is usual to rest those claims and aspirations of the labouring classes, which nevertheless the author, on better grounds, supports. No blind partisan on either side of the feud of labour against capital, will relish the book; but few persons of intelligence and impartiality who read it through, will lay it down without having reason to feel that they understand better than before some of the bearings of the questions involved in that conflict.

To this great practical merit are to be added two of a more theoretic kind, to the value of which I am the more called upon to bear testimony, as on the particular points touched upon in this department I shall have to express more difference than agreement. First: it contains a discussion of one of the fundamental questions of abstract political economy (the influence of demand and supply on price), which is a real contribution to science, though, in my estimation, an addition, and not, as the author thinks, a correction, to the received doctrine. Secondly: in the attempt to go to the very bottom of the question, what are the just rights of labour on one side, and capital on the other, it raises the great issues respecting the foundation of right and wrong, of justice and injustice, in a manner highly provocative of thought. To lay down a definite doctrine of social justice, as well as a distinct view of the natural laws of the exchange of commodities, as the basis for the deductions of a work devoted to such a subject as the principles and practice of Trades-Unionism, was inseparable from the thoroughness with which the author has sought to do his work.

Every opinion as to the relative rights of labourers and employers, involves expressly or tacitly some theory of justice, and it cannot be indifferent to know what theory. Neither, again, can it be decided in what manner the combined proceedings of labourers or of employers affect the interests of either side, without a clear view of the causes which govern the bargain between them -- without a sound theory of the law of wages.

Indeed, a theory of wages obtrusively meets the inquirer, at the threshold of every question respecting the relations between labourers and employers, and is commonly regarded as rendering superfluous any further argument.

It is laid down that wages, by an irresistible law, depend on the demand and supply of labour, and can in no circumstances be either more or less than what will distribute the existing wages-fund among the existing number of competitors for employment. Those who are content to set out from generally-received doctrines as from self-evident axioms, are satisfied with this, and inquire no further. But those who use their own understanding, and look closely into what they assent to, are bound to ask themselves whether or in what sense wages do depend on the demand and supply of labour, and what is meant by the wages-fund.

The author of this work has asked himself these questions; and while he is, as his writings give evidence, well versed in political economy, and is able to hold his ground with the best in following out economical laws into their more obscure and intricate workings, he has become convinced that the barrier which seems to close the entrance into one of the most important provinces of economical and social inquiry, is a shadow which will vanish if we go boldly up to it. He is of opinion that economists have mistaken the scientific law not only of the price of labour, but of prices in general. It is an error, he thinks, that price, or value in exchange, depends on supply and demand.