'Modern Atheism' in the ’National Review,' a quarterly organ of the unitarians, and the anti-reUgious tone of the book caused much adverse criticism.
During the writing of 'The Principles of Psychology' Spencer's health finally gave way. While engaged upon it, he stayed at various country places, and the continuous hard work, unrelieved by society, caused a nervous breakdown from which he never afterwards recovered. The disorder took the form of a peculiar sensation in the head, which came on when he tried to think, as a result of cerebral congestion, and led to inveterate insomnia. For eighteen months he travelled in various country places, avoiding all kinds of work and excitement, spending some of his time in fishing. At length it became necessary for him to earn money ; and, though little improved, he returned to London at the end of 1856, and wrote the article on 'Progress : its Law and Cause' for the 'Westminster Review,' foreshadowing one of the doctrines of 'First Principles.' Other articles followed : and although his health remained dis-organised, he was able with frequent breaks to carry on a certain amount of work.
It was in 1857 that the idea of writing a system of philosophy first occurred to Spencer. In that year he was engaged in revising his essays to be re-published in a single volume ; and the successive reading of the scattered ideas embodied in them revealed to him a marked unity of principle. They all adopted a naturalistic interpretation of phenomena, they were nearly all founded upon the doctrine of evolution. In the early days of 1858 he drew up a plan for a system of philosophy in which these fundamental principles were to be set forth, and their applications traced. To obtain the necessary leisure, he endeavoured to obtain various official posts, with the help of strong testimonials from John Stuart Mill 1 and others ; but finding his efforts fruitless, he at length hit upon the plan of issuing the work by subscription. In 1860 the programme of the 'Philosophy' was published, and subscriptions invited at the rate of 10s. a year for four quarterly instalments. With the help of friends a strong backing of weighty names was secured, and over 1 400 subscribers were registered in England ; while m America Professor E. L. Youmans helped to obtain about 200 more. With this arrangement Spencer commenced to write 'First Principles' ; but he soon found difficulties in his way. A nervous break-down involved a delay of a month or two in the issue of the first instalment. Repetition of these attacks before long caused him to abandon all attempt to keep regular intervals between the issues. Subscribers moreover did not pay up as well as was hoped ; but the death of his uncle William Spencer, bringing a legacy, saved the situation. The book was at last completed in 1862. It was received with little attention ; the few notices were mainly devoted to adverse criticism of the metaphysical portion. During the writing of 'First Principles' Spencer collected together four essays written for reviews, to form the four chapters of his book on 'Education,' of which the first edition appeared in 1861. This famous work, now translated into all the chief languages of the world and into many of the minor languages such as Arabic and Mohawk, strongly urged the claims of science, both as intrinsically the most useful knowledge, and as the best mental discipline. The method of education advocated resembles that of Pestalozzi in aiming at a natural development of the intelligence, and creating pleasurable interest. The child is to be trained, not by the commands and prohibitions of its parents, enforced by punishments, but by giving it the greatest possible amount of freedom, and allowing the natural consequences of wrong actions to be felt by it, without parental interference. The 'Education' has had an enormous influence, and is still recognised as a leading text-book.
The two years following the publication of 'First Principles' were devoted to the first volume of 'The Principles of Biology,' published in 1864. Since Spencer had not a specialist's knowledge of biology, he arranged with his friends Huxley and Sir Joseph Hooker [q. v. Suppl. II] to read the proofs. The publication evoked little notice : a fate which likewise befell a second series of 'Essays,' which he re-published the previous year. Other occupations of 1864 were the essay on the 'Classification of the Sciences,' published as a separate brochure, to which was appended 'Reasons for dissenting from the Philosophy of M. Comte.' Spencer's branched classification undoubtedly represents a great advance on the linear classification of the older philosopher. The second volume of the 'Biology' was commenced immediately on the conclusion of the first, and published in 1867. But before it was completed, Spencer's financial position obliged him to give subscribers notice of cessation. The diminution in the number of subscribers, and the difficulty of collecting their sub-
