But Mr. Hennah, who has had much practical experience, recommends the collodion to be made sensitive merely by the iodide of potassium; and he said, "if it did not work quite clearly and well, a little tincture of iodine brought it right." Here, then, is added the very thing which MR. CROOKES proposes to abstract. Again, MR. CROOKES considers the free iodine to be the cause of the colouring of the collodion; will he then kindly explain its _modus operandi_? As he has on several occasions given your readers the benefit of his great chemical knowledge, I trust they may be favoured by him with a solution of these difficulties, which have puzzled AN AMATEUR. * * * * * Replies to Minor Queries. _Admissions to Inns of Court_ (Vol. viii., p. 540.).--The following particulars may be of service to your correspondent who requires information upon the subject of the matriculations at the inns of court. The books of Lincoln's Inn, which record the calls to the bar and other proceedings of the Society, commence in the second year of the reign of Henry VI., 1423. Those of the Inner Temple, which contain the admittances in 1547, and the calls to the bar in 1590; of the Middle Temple, which contain a regular series of admissions and calls, about the year 1600; and of Gray's Inn, about the year 1650. The earlier records of Gray's Inn were destroyed by fire, but the Harleian MS. No. 1912., in the British Museum, contains: An alphabetical list of gentlemen admitted to that society, with the dates of their admission, from 1521 to 1674. Table of the admittances into Gray's Inn, declaring the names of the gentlemen, the town and country whence they came, and the day, month, and year when admitted, from the year 1626 to 1677. Arms and names of noblemen and knights admitted to the said society. An alphabetical list of all persons called to the bar by the said society. The Lansdowne MS. No. 106., which is also in the British Museum, contains: Names of benchers, associates, utter barristers, &c. of Lincoln's Inn, and the same of the Inner Temple; and of the students of the several Inns of Court, apparently about the end of the reign of Elizabeth. JAS. WHISHAW. Gower Street. The MS. Harl. 1912. contains the admissions to Gray's Inn. G. STEINMAN STEINMAN.