P.S.--The petition from the Livery, doubtless agreed to in Common Hall, which the king refused to receive, and which is referred to above, is most probably the one which ÆGROTUS inquires about, and of which the Duke complains in his dispatch of Jan. 1810. I have not been able to see it; but if I can find it, will send you notes of it; the mem. I have sent establishes the fact of its having been carried. _Reichenbach's Ghosts_ (Vol. iv., p. 5.; Vol. v., p. 89.).--If A. N. will do me the favour to refer to my question, he will see that his remarks do not furnish a reply. Reichenbach says, that "thousands of ghost stories will now receive a natural explanation," from his discovery that the decomposition of animal matter is accompanied by light, or luminous vapour, which is visible to certain sensitive persons. As I originally stated, "my Query is, _where to find_ the 'thousands of ghost stories' which are explained by it." I now repeat that Query in unaffected ignorance. I have read a good many ghost stories, British and foreign; but I know that some of the writers in "N. & Q." are much better acquainted with German literature and superstitions than I am; and I ask them if they can tell me where to find _such_ stories,--that is, ghost stories explained by Reichenbach's discovery? I do not ask for "thousands," nor even hundreds--a score or two will be quite enough; or even a dozen, if they are good ones. S. R. MAITLAND. Gloucester. _The Broad Arrow._--I can only offer the following note on the above subject as a conjecture, probably most of your readers will think a very wild one. It has sometimes occurred to me that the origin of the symbol now generally known as the "broad arrow" might be traced back to the mysteries of Mithras. At all events, it is known that the same figure occurs on coins, gems, &c. as the symbol of Mithras as the _Sun_. Now, so widely was the worship of Mithras spread throughout the Roman empire, that I believe no one would feel any surprise at the adoption of a Mithraic symbol even in the remotest parts of the empire; and indeed the fact that Carausius, during his usurpation of the imperial authority in Britain, issued coins with the inscription Ἡλίῳ Μίθρᾳ ἀνικήτῳ, brings the worship of Mithras, as it were, home to our own doors. Whether the symbol of the sun was ever employed for any such purpose as our modern broad arrow, is a question on which I hope some of your readers may be able to throw some light. Meanwhile, being quite ignorant as to the antiquity of our Ordnance mark, the above is merely thrown out as a conjecture. It is perhaps, to some extent, confirmed by a statement of Grimm's (_Deutsche Mythologie_), that the symbol of the _Moon_ was used by the ancient Germans precisely as our broad arrow, viz. on boundary stones, &c.