Powerful as this extraordinary agent has become, and incalculably useful as its operation is now found to be, it would appear that the principle of the electric telegraph and its _modus operandi_, almost identically as at present, were known and described upwards of a century ago. On the occasion of a late visit to Robert Baird, Esq., of Auchmeddan, at his residence, Cadder House, near Glasgow, my attention was called by that gentleman to a letter initialed C. M., dated Renfrew, Feb. 15, 1753, and published that year in the _Scots Magazine_, vol. xv. p. 73., where the writer not only suggests electricity as a medium for conveying messages and signals, but details with singular minuteness the method of opening and maintaining lingual communication between remote points, a method which, with only few improvements, has now been so eminently successful. It is usual to attribute this wonderful discovery to the united labours of Mr. W. F. Cooke and Professor Wheatstone, but has any one acknowledged the contribution of C. M., and can any of the learned correspondents of "N. & Q." inform me who he was? INQUIRENDO. Glasgow. * * * * * Minor Queries. _Queries relating to the Porter Family._--Above the inscription on the tablet erected by a devoted friend to the memory of this highly-gifted family in Bristol Cathedral, is a medallion of a portcullis surrounded by the word AGINCOURT, and surmounted by the date 1415.--What connexion is there between Agincourt[2] and the Porter family? {365} Did Sir R. K. Porter write on account of Sir John Moore's campaign in the Peninsula?--What is the title of the book, and where can it be procured?[3] Who was Charles Lempriere Porter (who died Feb. 14, 1831, aged thirty-one), mentioned on the Porter tombstone in St. Paul's churchyard at Bristol?--Who was Phoebe, wife of Dr. Porter, who died Feb. 20, 1845, aged seventy-nine, and whose name also occurs on this stone? Did this family (which is now supposed to be extinct) claim descent from Endymion Porter, the loyal and devoted adherent of King Charles the Martyr? D. Y. N. [Footnote 2: It refers to Sir Robert Ker Porter's third great battle-piece, AGINCOURT: which memorable battle took place October 25, 1415. Sir Robert presented it to the city of London, and it is still in the possession of the corporation: it was hung up in the Guildhall a few years since.] [Footnote 3: In 1808, Sir R. K. Porter accompanied Sir John Moore's expedition to the Peninsula, and attended the campaign throughout, up to the closing catastrophe of the battle of Corunna. On his return to England, he published anonymously, _Letters from Portugal and Spain, written during the March of the Troops under Sir John Moore_, 1809, 8vo.--ED.] _Lord Ball of Bagshot._--Coryat, in his _Crudities_, vol. ii. p. 471., edit. 1776, tells us that at St. Gewere, near Ober-Wesel--