In 1806 Turner began his _Liber Studiorum_, in rivalship of Claude's _Liber Veritatis_; it was issued in parts in dark blue covers, each part containing five plates. It was discontinued in 1814, after seventy plates had been issued. Although not remunerative at the time, in later days as high as three thousand pounds has been paid for a single copy of the _Liber_, while the subscription price was only seventeen pounds ten shillings; even before Turner died a copy of it was worth over thirty guineas. Charles Turner, the engraver, used the proofs for kindling-paper; but some years later Colnaghi, the print dealer, paid him fifteen hundred pounds for his remaining "rubbish," as he considered it. "Good God!" cried the old engraver; "I have been burning bank-notes all my life!" In 1878 Professor Norton, of Harvard University, published a set of thirty-three of the best of the _Liber_ studies, reproduced in Boston by the heliotype process. The _Liber Studiorum_ was intended to manifest Turner's command of the whole compass of the landscape art, and was divided into six heads: historical, pastoral, elegant pastoral, mountain, marine, and architectural. In 1808 Turner was appointed Professor of Perspective in the Royal Academy. During two or three years only, out of the thirty in which he held the professorship, did he deliver lectures. He spoke in a deep and mumbling voice, was confused and tedious in manner, and frequently became hopelessly entangled in blind mazes of obscure words. Sometimes when he had written out his lectures he was unable to read them. Once, after fumbling in his pockets, he exclaimed: "Gentlemen, I've been and left my lecture in the hackney-coach." Still he was interested in this work, and Ruskin says: "The zealous care with which Turner endeavored to do his duty is proved by a large existing series of drawings, exquisitely tinted, and often completely colored, all by his own hand, of the most difficult perspective subjects--illustrating not only directions of light, but effects of light, with a care and completion which would put the work of any ordinary teacher to utter shame." During this year he took a house at Hammersmith, Upper Mall, the garden of which ran down to the Thames, but still retained his residence in Harley Street. In 1812 he first occupied the house No. 47 Queen Anne Street, and this house he retained for forty years. It was dull, dingy, unpainted, weather-beaten, sooty, with unwashed windows and shaky doors, and seemed the very abode of poverty, and yet when Turner died his estate was sworn as under one hundred and forty thousand pounds--seven hundred thousand dollars. When Turner's father died in 1830 he was succeeded by a withered and sluttish old woman named Danby. The whole house was dreary, dirty, damp, and full of litter. The master had a fancy for tailless--Manx--cats, and these made their beds everywhere without disturbance. In the gallery were thirty thousand fine proofs of