Thus, if labour were 20d. per diem in 1640, and is 40d. at this time, 1000_l_. in 1640 is equivalent to 500l. (only half as much) now. But, on the contrary, as the cost of production of numerous articles by machinery, &c. has been _by so much_ reduced, the power of purchase now, as compared with 1640, of 1000l., is _by so much_ increased. The article itself must determine by how much. The question put by C. H. is too general to admit of a positive solution; but should he specify the commodity and place of investment in the seventeenth century and to-day of the 1000l., our statistics might still be at fault, and deny us even a proximate determination of his inquiry. Even his 1000l., which he may consider a fixed measure of value, or _punctum comparationis_, is varying in value (=power of purchase) daily, even hourly, as regards almost every exchangeable product. Tooke _On Prices_ is a first-rate authority on this subject. T. J. BUCKTON. Lichfield. _Grammars for Public Schools_ (Vol. ix., pp. 8. 209.).--Pray add this little gem to your list, now scarce: "The Gate of Tongues Unlocked and Opened, or else A Seminarie or Seed Plot of all Tongues and Sciences, that is, a short way of teaching and thorowly learning, within a yeare and a half at the farthest, the Latin, English, French, and any other tongue, together with the ground and foundation of Arts and Sciences, comprised under an hundred Titles and 1058 Periods. In Latine first, and now as a token of thankfulnesse brought to light in Latine, English, and French, in the behalfe of the most illustrious Prince Charles, and of British, French, and Irish Youths. By the labour and industry of John Anchoran, Licentiate of Divinity, London, 1633." Our British youths of those days seem to have been _apt scholars_. I. T. ABBOTT. Darlington. _Classic Authors and the Jews_ (Vol. ix., pp. 221. 384.).--Any edition of the _Historiæ Augustæ Scriptores Sex_, containing an index, ought to supply B. H. C. with a few additional references. See, for instance, the Index to the Bipont Edition, 2 vols. 8vo., [MDCCLXXXVII], under the words "Judæi," "Judaicus," "Moses." C. FORBES. Temple.