win's 'Enquirer,' published in 1797, led to discussions between Malthus and his father about some of the questions already handled by the same author in his 'Political Justice,' 1793. Malthus finally resolved to put his reasons upon paper for the sake of clearness. He was thus led to write the 'Essay on Population,' published anonymously in 1798. Godwin had dreamt of a speedy millennium of universal equality and prosperity. He had already briefly noticed in his 'Political Justice' the difficulties arising from an excessive stimulus to population. Malthus brought them out more forcibly and systematically. He laid down his famous principle that population increases in a geometrical, and subsistence only in an arithmetical ratio, and argued that population is necessarily limited by the 'checks' of vice and misery. The pamphlet attracted much notice. Malthus was replying to an 'obliging' letter from Godwin in August 1798 (Paul, Godwin, i. 321). In 1801 Godwin replied to Malthus (as well as to Parr and Mackintosh) in his 'Thoughts on Dr. Parr's Spital Sermon.' He was both courteous and ready to make some concessions to Malthus. Malthus soon came to see, as his letter to Godwin already indicates, that a revision of his arguments was desirable. In 1799 he travelled in order to collect information. He went with E. D. Clarke [q. v.], J. M. Cripps [q. v.], and William Otter [q. v.] to Hamburg, and thence to Sweden, where the party separated. Malthus and Otter went through Sweden to Norway, Finland, and Russia. Malthus added some notes to the later editions of Clarke's 'Travels.' His father died in 1800. In 1802 he took advantage of the peace to visit France and Switzerland. In 1800 he had published a tract upon the 'High Price of Provisions,' and promised in the conclusion a new edition of his essay. This, which appeared in June 1803, was a substantially new book, containing the results of his careful inquiries on the continent and his wide reading of the appropriate literature. He now explicitly and fully recognised the ' prudential ' check implicitly contained to some degree in the earlier essay, and repudiated the imputation to which the earlier book had given some plausibility. The 'checks 'no longer appeared as insuperable obstacles to all social improvement, but as defining the dangers which must be avoided if improvement is to be achieved. He always rejected some doctrines really put forward by Condorcet which have been fathered upon him by later Malthusians. He made converts, and was especially proud (Empson) of having convinced Pitt and Paley.
On 13 March 1804 Malthus married Harriet, daughter of John Eckersall of Claverton House, St. Catherine's, near Bath. At the end of 1805 he became professor of history and political economy at the newly founded college of Haileybury. He took part in the services of the college chapel, and he gave lectures on political economy, which, as he declares, the hearers not only understood, but 'did not even find dull.' The lectures led him to consider the problem of rent. The theory at which he arrived is partly indicated in two pamphlets upon the corn laws, published in 1814 and 1815, and is fully given in the tract upon 'The Nature and Progress of Rent' (which was being printed in January 1815). The doctrine thus formulated has been generally accepted by later economists. A similar view had been taken by James Anderson (1739-1808) [q. v.] The same doctrine was independently reached by Sir Edward West, and stated in his 'Essay on the Application of Capital to Land … by a Fellow of University College, Oxford,' published in the same year as Malthus's pamphlet. Ricardo, in an essay on 'The Influence of a Low Price of Corn on the Profits of Stock,' while replying to the two tracts in which Malthus had advocated some degree of protection, substantially accepted the theory of rent, although they differed upon certain questions involved (see Bonar, pp. 238-45). Malthus's 'Political Economy,' published in 1820, sums up the opinions to which he had been led upon various topics, and explains his differences from Ricardo, but is not a systematic treatment of the subject.
Malthus lived quietly at Haileybury for the rest of his life. He visited Ireland in 1817, and in 1825, after the loss of a daughter, travelled on the continent for his own health and his wife's. He was elected F.R.S. in 1819. In 1821 he became a member of the Political Economy Club, founded in that year by Thomas Tooke ; James Mill, Grote, and Ricardo being among his colleagues. Professor Bain says that the survivors long remembered the ' crushing' attacks of James Mill upon Malthus's speeches. He was elected in the beginning of 1824 one of the ten royal associates of the Royal Society of Literature, each of whom received a hundred guineas yearly during the life of George IV, William IV declining to continue the subscription (Jerdan, Autobiography, iii. 159, 162). He contributed papers to the society in 1825 and 1827 upon the measure of value. He was also one of the first fellows of the Statistical Society, founded in March 1834. He wrote several papers and revised his 'Political Economy' during this period, and he gave some