390 



NOTES AND QUERIES. 



[Nov. 17. 1855. 



but, tvithont the gold bath first applied, it unfortunately 

 removes the picture itself with. it. 



When ammonia is used as a fixing agent, it should not 

 be exposed to ordinary daylight at tlie time of operating, 

 as the chloride of silver when dissolved in this menstrum, 

 is exceeding susceptible of the actrinic influence. 



I abstain for the present from giving formulae, as the 

 principles are capable of application to almost any mode 

 of proceeding, but shall be happy to furnish them if 

 desired. ' Geo. Siiadboi.t. 



Single Stereoscopic Pictures. — Having been allowed to 

 express my opinions in "N. & Q." on the subject of 

 stereoscopic angles, perhaps I may be permitted to offer a 

 few words on the subject of Mr. Nokman's mode of taking I 

 single stereoscopic pictures by one lens ; and am induced 

 to make this request, because, as far as I am capable of 

 thinking, those who have mooted the question in "N. & 

 Q." have left it unsettled. I consider that Mu. Norman's 

 method (ingenious as it undoubtedlj' is) is optically in- 

 correct ; and am at a loss to understand how two incorrect 

 pictures, blended in one, can i-esult in a picture which, 

 when seen by one e^'e, can be " wonderfully," or even 

 satisfactoril}', stereoscopic. If I rightly compi-ehend the 

 method proposed by Mr. Noejian, it is this : there are 

 two apertures, 2h inches apart, in a piece of wood or other 

 material, placed before one lens, through which the 

 pictures arc received and blended in one, which is the 

 picture taken. This picture, I have said, is optically in- 

 correct: and, I believe, the following experiment will 

 sl:ow that it must be so. Let there be a row of six 

 columns, at 12 feet apart, numbered 1, 2, 3, &c., beginning 

 at the left hand. Kow, the light from these columns, in 

 its passage through the lens, will be more and more re- 

 fracted as it approaches the outsides of the lens : conse- 

 quently, in the picture produced by the aperture on the 

 left side, the columns 1 and 2 will be nearer together than 

 5 and C> ; whilst in that at the right, 1 and 2 will be wider 

 apart than 5 and G, so that t^vo pictures, incorrect 

 throughout their whole range, will bo blended together in 

 one. 



That such must be the case, any one who understands 

 the nature of a lens, and who can draw a very simple 

 diagram, can satisfy himself. 



This being the true state of the case, I am at a loss to 

 understand how such a jumble (for such it is) can pro- 

 duce, when seen with either one or both eyes, stereoscopic 

 eftect — or, I would rather say, satisfactory stereoscopic 

 effect. 



If the passage of light through a lens be considered, it 

 will be evident that no single lens can produce two cor- 

 rect pictures; and that, therefore, Mr. Norman's niethod 

 must, as an optical necessity, fail. It is also equally 

 clear that two lenses, 2i inches apart, must be used, if 

 two correct pictures are to result. But, whether such 

 pictures could be superposed, is a question, the answer 

 to v.'hich, I should incline to believe, must be no. Then 

 there remains another question (and a most intei'esting 

 one it is), would the two correct pictures so blended pro- 

 duce due stereoscopic effect? T. L. Meuritt. 



Maidstone, 



Bound Towers of Kerry (Vol. xii., p. 345,). — 

 A letter appeared in " N, & (2." of the 3rd inst., 

 signed R. H., who, I presume, lives not one 

 hundred miles from Trinity College here, in refer- 

 ence to an old book on the Round Towers of Kerry, 

 which appeared in a recent catalogue of mine, and 



No. 316.] 



which I only sold a few days since. R, H. seem- 

 ingly doubts the existence of this book, but the 

 purchaser, if he thinks it worth while, can very 

 easil}"^ remove his doubts. As you gave publicity 

 to R. H.'s letter, I trust you will do me the favour 

 of publishing this reply. John O'Daly. 



Dublin. 



[We have omitted some passages from this communi- 

 cation, as Mr. O'Daly is clearlj' under an erroneous im- 

 pression as to the question at issue. No one doubts the 

 existence of the book catalogued by Mr. O'Dai.y, nor 

 questions the accuracy of the account given by him. But 

 it is well known that books occasionally turn up which 

 were not printed at the places nor at the times named on 

 their title-pages. An inquiry whether the book alluded 

 to was not a book of that class, which was the inquiry 

 made by our correspondents, convej-ed no imputation on 

 Mr. O'Daly. Mr. O'Daly has also overlooked the fact, 

 that the doubts expressed by E. H. are shared by that 

 accomplished antiquary, the Eev. James Gra-ses, of Kil- 

 kenny. It is to be hoped, for the interest of antiquarian 

 literature, that INIr. O'Daly will bring the question under 

 the notice of the gentleman who purchased the book 

 and who, under the circumstances, we cannot doubt will 

 take such steps as he may think desirable for establishing 

 the genuineness of this remarkable volume. 



These remarks were in tj'pe when we received a second 

 letter from Mr. O'Daly, to v,hieh tlie preceding para- 

 graph is an answer, — Ed. " N. & Q."] 



Dr. Broxholme (Vol, xii., pp. 303. 353.). — The 

 followiwg extract, from the Life of Dr. George 

 Cheijne (Oxford, 1846, p. 88.), supplies some par- 

 ticulars respecting Dr. Broxholme which are not 

 mentioned by Dr. Monk (p. 353.) : 



"Noel Broxholme was born in the year 1G8G; ad- 

 mitted a king's scholar at Westminster in 1700 ; elected 

 student of Christ Church, Oxford, in 1705 ; M.A. in 1711 ; 

 elected one of the first of Dr. Radclitfe's Travelling Fel- 

 lows in 1715; M.B. and M.D. in 172.3; delivered the 

 Harveian Oration, which was printed, in 1731 ; appointed 

 Phj'sician to Frederick, Prince of Wales, in 1734; died 

 at Hampton Court in 1748 ; and left in bis will a legacy 

 of 500/. for the benefit of four of the king's scholars at 

 VVestminster, on their election to the Universities. — 

 Nichols's Liter. Anecd., vol. i. p. 484. ; 0.i-f. Calendar ; 

 Calal. of Oxf. Graduates." 



M. D. 



Contributors to Defence of Parliament (Vol. xii., 

 p. 360.). — First line, at the top of the page, for 

 '•[Qy. Sir Rich. Rice?]," read [Qy. Sir Rich. 

 Price ?]. I wish to correct the above very trifling 

 error, inasmuch as the conjecture I hazarded as 

 to the right reading of the name, to which it is 

 appended, is plainly even then sufficiently remote ; 

 but it was the only patronimic in any list of the 

 Long Parliament that I had access tp, that at all 

 bore the very slightest resemblance to the name 

 in my MS-, which, I confess, I was quite at a loss 

 to decipher satisfactorily in this instance. The 

 Christian name (though not the prefix) corre- 

 sponds, it will be seen ; but neither " Powerys," 

 or "Price," I fear, correctly renders the original. 

 A Sir Rich. Price, hovyever, did sit (for Cardigan- 

 shire) in this parliament. 



