432 



NOTES AND QUERIES. 



[2nd g. N« 74., May 30. '57, 



cal and statistical purposes, and supply clues where 

 other sources f\ul. I have often had occasion to 

 avail myself of Mr. Maclaurin's collection, and 

 have found it very useful. 



The earliest volume is entitled — 



"A complete Guide to all Persons who have any Trade 

 or Concern with the City of London and Parts adjacent, 

 containing ; 



1. Names of Streets, &c. 



2. Names and Situation of Churches and Public Buildings. 



3. An account of Stage Coaches, &c. 



4. The Kates of AYatermen and Hackney Coachmen, and 



Post Office Intelligence. 

 6, The Names and Places of Abode of the most eminent 

 Merchants and Traders in and about London. 



6. Useful Tables of the Value of Goods. 



7. Tables of Interest, being the exactest piece of the kind 



hitherto published, and designed for the Use of Per- 

 sons of all Degrees, Natives or Foreigners. 



" The Second Edition, with large Additions and Altera- 

 tions. London, printed for J. Osborn, at the Golden Ball, 

 in Paternoster Row. 1740." 



Small octavo, 180 pages. 



The next volume is the third edition of the 

 same publication, date 1744. After which period 

 the collection is nearly consecutive. Among them 

 are — • 



'• A List of the Livery of London, with their Places of 

 Abode and Businesses ; by Thomas Tomlins, Clerk to the 

 Worshipful Company of Painters." Date about 1750, 



Kent's Directory, 1754, and a 



" Directory to the Nobility, Gentry, and Families of Dis- 

 tinction in London and Westminster, being a Supplement 

 to the British Directory of Trade, Commerce, and Manu- 

 factures." 1793. 



It contains also a list of the Livery of London 

 at that period. 



There is also a collection of London Directories 

 at the Guildhall Library, which ought to possess 

 the most complete collection of these registers of 

 trade and commerce, for there is the place where 

 they would be expected to be found ; but it is 

 only of late years that that library has received 

 much attention. Any person possessed of old 

 directories could not do better than send them 

 there. G. R. C. 



PHOTOGRArHIC COKBESPONDENCE. 



Stereoscopic Angles. — Some three years ago, when 

 photographers were all at sea on the subject of stereo- 

 scopic angles, I stated in " N. & Q." that the correct span 

 between the cameras was 2J inches. To this Mr. G. 

 Shadbolt raised some objections, which led to several 

 Notes between us about the matter ; and which he closed 

 by saying he supposed he must be classed amongst the 

 incorrigibles, as be entirely differed from me. Now, I 

 perceive that at the last meeting of the London Photo- 

 graphic Society, he gave to the members, just as if it 

 were his own, precisely my method ; which I think was a 

 disingenuous mode of expressing his conviction, for he 

 could not have forgotten all that passed between us be- 

 fore. It was, in fact, appropriating to himself the pub- 

 licly expressed opinions of another, whom he had opposed. 



As what was said by myself and Mr. Shadbolt 



appeared in " N. & Q.," I think it would not be out of 

 place, if I may, through the same medium, offer my con- 

 gratulations to that gentleman on this thorough change 

 in his opinion ; as my only object was to prove the cor- 

 rectness of my views, and I am glad to find a convert in 

 one so incorrigible. ■ T. L. Merkitt. 



Star Hill, Rochester, May 24, 1857. 



Hardioick's "Photographic Chemistry" — The fourth 

 edition of this most useful volume has just been issued. 

 The author keeps pace with the improvements which are 

 daily being introduced into the science of photography. 

 Among these are the experiments on the manufacture of 

 collodion, throwing further light on the conditions which 

 affect the sensitiveness of the excited film ; the introduc- 

 tion of glycyrrhizine, the dry collodion, oxymel pre- 

 servative, and albumenised collodion processes ; so that 

 the amateur and professional photographer finds in Mr. 

 Hardwick's indispensable companion, not only the most 

 important facts connected with the science, but the very 

 latest discoveries carefully and clearly recorded. 



Optical Queries. — In Sir David Brewster's Treatise on 

 Optics, the radii ("computed by Sir J. Herschel") of two 

 combinations of lenses free from spherical aberration are 

 given (p. 58.) In both, the radii of the bi-convex lenses 

 are those of the best form of bi-convex, viz. 1 to G. The 

 radii of the meniscus in the first combination are as 17 to 

 29 (this ratio is correct to three places of decimals) ; in 

 the second as 1027 to 4064. I am anxious to know : — 



1. Are these the only ratios the radii of the meniscus 

 may have? 



2. Is it immaterial which of the ratios be adopted? 



3. Will a formula, deduced from either of the examples 

 given, produce a combination free from spherical aberra- 

 tions ? 



4. If so, why is not a combination of the kind adopted 

 in the lenses used for photography ? 



Perhaps some of your scientific correspondents, or Sir 

 David Brewster himself, Avill obligingly give me informa- 

 tion on these points ? Bloice. 



Mr^Xt'fjS t0 Minax dhutxits. 



Bishop Philip Ellis, O.S.B. (2"-^ S. iii. 406.)— 

 A full account of this prelate has lately been pub- 

 lished by Rev. George Oliver, D.D., of Exeter, in 

 his Collections illustrating the History of the Ca- 

 tholic Religion in the Counties of Cornwall, Devon, 

 Dorset, Somerset, Wilts, and Gloucester (Dolman, 

 London). If J. W. H. will refer to this valuable 

 compilation (pp. 294. 511.), he will find probably 

 all that is known of the life, death, and works, 

 chiefly Sermons, of this prelate, Bishopof Aure- 

 liopolis in partibus, and Vicar Apostolic of the 

 Western District in England, and subsequently 

 Bishop of Segni in the Campagna di Roma. 



^ ^ F. C. H. 



Porson Fund (2"'* S. iii. 368.) — The Editor is 

 authorised to state, in answer to Q. 1., that, after 

 the endowment of the " Porson Prize," the residue 

 of the fund raised for the benefit of Professor 

 Porson, with its accumulations, was invested "in 

 the names of the Chancellor, Masters, and Scho- 

 lars of the University of Cambridge, upon certain 

 trusts, for the purpose of founding a scholarship, to 



