But, he lacked a desire to pursue the legal profession, and over some ensuing years, he devoted himself to writing in various publications about social and economic questions and treatises that related to Ireland.

It followed up on and expanded J. S. Mill's treatment in the Essays on some Unsettled Questions in Political Economy, and formed an admirable introduction to the study of economics as a science.

Logical exactness, precision of language, and firm grasp of the true nature of economic facts are the qualities characteristic of this as of all his other works.

If the book had done nothing more, it would still have conferred an inestimable benefit on political economists by its clear exposition of the true nature and meaning of the ambiguous term law.

[3] In 1861, Cairnes was appointed to the professorship of jurisprudence and political economy in Queens College Galway, and in the following year he published his admirable work The Slave Power, one of the finest specimens of applied economic philosophy.

The inherent disadvantages of the employment of slave labour were exposed with great fulness and ability, and the conclusions arrived at have taken their place among the recognised doctrines of political economy.

The opinions expressed by Cairnes as to the probable issue of American Civil War were largely verified by the actual course of events, and the appearance of the book had a marked influence on the attitude taken by serious political thinkers in England towards the Confederate States of America.

His health soon rendered it impossible for him to discharge his public duties; he resigned from his post in 1872 and retired with the honorary title of professor emeritus of political economy.

The last years of Cairnes' life were spent in the collection and publication of some scattered papers, contributing to various reviews and magazines, and in the preparation of his most extensive and important work.

In 1874, appeared his largest work, Some Leading Principles of Political Economy, newly Expounded, which is beyond doubt a worthy successor to the great treatises of Adam Smith, Thomas Malthus, David Ricardo and John Stuart Mill.

It does not expound a completed system of political economy; many important doctrines are left untouched; and in general, the treatment of problems is not such as would be suited for a systematic manual.

It may be called a positive science, because its premises are facts, but it is hypothetical in so far as the laws it lays down are only approximately true, i.e. are only valid in the absence of counteracting agencies.

[4] From this view of the nature of the science, it follows at once that the method to be pursued must be that called by Mill the physical or concrete deductive, which starts from certain known causes, investigates their consequences and verifies or tests the result by comparison with facts of experience.

It may, perhaps, be thought that Cairnes gives too little attention to the effects of the organism of society on economic facts, and that he is disposed to overlook what Walter Bagehot called the postulates of political economy.

At the same time, it may be thought that Cairnes overlooked a point brought forward prominently by Senior, who also had called attention to the bearing of competition on the relation between cost of production and value.