Purcell was then sixteen years old, and his boy-soprano voice must have been near its breaking--perhaps it had already departed. It was, however, the good custom of the period to retain as supernumeraries of the King's Chapel any of the old boys who gave evidence of musical ability. In 1666 we find "Hen. Cooke, Thomas Purcell, and other Gentlemen of the Chapel Royal, petition on behalf of themselves, the pages of the chapel, and _boys whose voices have changed_, for payment, there being no money assigned to the treasurer of the chamber for those purposes." Purcell therefore continued attached to the Chapel Royal, and became a pupil of Dr. John Blow, the successor to Pelham Humphreys, as "Master of the Children." That Purcell studied under Blow is certain from the inscription on Blow's monument in Westminster Abbey, where it is stated that he was "master to the famous Henry Purcell." Blow was undoubtedly the very master Purcell then needed, for he was eminent for his goodness, amiability, and moral character, and combined with those excellent qualities all the learning and experience of a sound musician. His compositions are remarkable for their melodies and the boldness of their harmonical progressions.[19] He held appointments at the Chapel Royal, Westminster Abbey, St. Paul's Cathedral, and St. Margaret's, Westminster; and it speaks strongly for his singleness of heart, and the total absence of envy and jealousy in his nature, that recognising and proclaiming the remarkable abilities of his pupils, Purcell and Jeremiah Clarke, he resigned his appointments at Westminster Abbey and St. Paul's Cathedral, in order that they might occupy those prominent and advantageous positions. This estimable man, Blow, survived his dear friend and pupil, Purcell, some years, and so became his successor at Westminster Abbey, and was eventually laid in a grave close to him, nearly beneath the organ where they had so often discoursed sweet music together. That Blow fully estimated the genius of his pupil Purcell, there can be no doubt, since many manuscript copies of the compositions of the latter exist in the handwriting of Blow. Probably it was at the suggestion of Blow that Purcell was appointed _copyist_[20] to Westminster Abbey in 1676. He succeeded the Rev. Stephen Byng, one of the minor canons, who probably resigned the post, as he did not die till 1681. Purcell was eighteen years of age when he became copyist of Westminster Abbey; hence arose the mistake made by Burney and Hawkins, and constantly repeated on their authority, that Purcell was appointed _organist_ of Westminster Abbey at eighteen. The office of copyist he held for two years only.