_Robert Johnson._--Perhaps some of your correspondents could give me some information relative to the pedigree of Robert Johnson, Esq., who was a baron of the Exchequer in Ireland in 1704; his parentage and descent; his wife's name and family; his armorial bearings; and date of his birth and death. Was he the Robert Johnson who entered Trinity College, Dublin, in 1671, as a Fellow Commoner at the age of fourteen? If so, his birthplace was London, and his father's name was also Robert. E. P. L. Co. Westmeath. _Selling a Wife._--What is the origin of the popular idea, that a man may legally dispose of his spouse by _haltering_ her, and exposing her for sale in a public market? Some time ago the custom appears to have been very prevalent; and only a few months back there was a paragraph in _The Times_, describing an occurrence of the kind at Nottingham. French romancers and dramatists have seized upon it as a leading trait of English society; and in their remarkably-faithful delineations of English life it is not unusual to find the blue-beard milord Anglais carting milady to Smithfield, and {430} enlarging upon her points in the cheap-jack style to the admiring drovers. V. T. STERNBERG. _Jock of Arden._--This worthy of the Robin Hood class of heroes, is understood to figure very prominently in the legendary history of Warwickshire. Where can any references to his real or supposed history be found, and what are the legends of which he is the hero? W. Q. _Inigo Jones._--Where can a full list of mansions and other important buildings, erected from designs after that great master architect Inigo Jones, be found? A CORRESPONDENT. _Dean Boyle._--Wanted, the pedigree of Richard Boyle, Dean of Limerick, and Bishop of Leighlin in 1661. He had a brother Roger, also in the church. Was he a grandson of John Boyle of Hereford, eldest brother of Roger, father of Richard, first Earl of Cork? This John married Alice, daughter of Alex. Hayworth, of Burdun Hall, Herefordshire. Y. S. M. Dublin. _Euphormio_ (Vol. i., p. 27.).--Mention is made of _Censura Euphormionis_ and other tracts, called forth by Barclay's works: where can some account of these be found? P. J. F. GANTILLON, B.A. _Optical Query._--Last summer the following illusion was pointed out to me at Sandwich, Kent. The ingenious horizontal machine to enable the treadmill to grind the wind, in default of more substantial matter, although certainly revolving only in one direction, say from right to left, at intervals appeared to change its direction and turn from left to right. This change appeared to several persons to take place at the same time, and did not seem to be owing to any shifting of the perpendicular shutters for regulating the resistance of the air. The point from which I viewed it was near the south door of St. Clement's Church. Have any of the readers of "N. & Q." noticed a similar illusion, and can they explain it? H. H. Gloucester.