June 4. 1853.] 



KOTES AND QUERIES. 



555 



But I thought it might be useful to give a general 

 indication of the sources from which the writer 

 drew, and therefore put in all that I could find, 

 without the expenditure of a great deal of time. 

 Consequently I fear that those I have omitted will 

 not be found to be the most obvious. 



I shall be glad to make a few remarks on some 

 of the passages noticed by L. 



P. 25. — Of this piece of carelessness — forwhich 

 I do not the less feel that I deserved a rebuke be- 

 cause L. has not administered it — I had already 

 been made aware by the kindness of a friend. I 

 confess I had never heard of Osorius, wliich is 

 perhaps no great matter for wonder ; but I looked 

 for his name both in Bayle and the catalogue of 

 the library of the British Museum, and by some 

 oversight missed it. I have since found it in both. 

 I cannot help, however, remarking that this is a 

 good example of the advantage of noting even/ 

 deviation from the received text. Had I tacitly 

 transposed three letters of the word in question (a 

 small liberty compared with some that my prede- 

 cessors have taken), my corruption of the text 

 might have passed unnoticed. I have not had 

 much experience in these things ; but if the works 

 of English writers in general have been tampered 

 with by editors as much as I have found the Ad- 

 vancement and Essays of Lord Bacon to be, I fear 

 they must have suffered great mutilation. I rather 

 incline to think it is the ease, for I have had occa- 

 sion lately to compare two editions of Paley's Horce 

 Pauliriie, and I find great differences in the text. 

 All this looks suspicious. 



P. 34. — I spent some time in searching for this 

 passage in Aristotle, but I could not discover it. 

 I did not look elsewhere. 



P. 60. — In the forthcoming edition of the JEssaijs 

 I have referred to Plutarch, Gr^Z/., 1., which I 

 incline to think is the passage Bacon had in his 

 mind. The passage quoted from Cicero I merely 

 meant to point out for comparison. 



P. 146. — The passage quoted is from Sen. ad 

 JLucil., 52. 



P. U7.—Ad Lucil, 53. 



P. 159.— Ad Lucil, 71. 



Two or three other passages from Seneca will 

 be found without any reference. One of them, 

 p. 13., " Quidam sunt tam umbratiles ut putent in 

 turbido esse quicquid in luce est," I have taken 

 some pains to hunt for, but hitherto without suc- 

 cess. Another noticeable one, " Vita sine pro- 

 posito languida et vaga est," is from Ep. ad Lucil., 

 95. 



For the reference to Aristotle I am much obliged. 

 I was anxious to trace all the quotations from 

 Aristotle, but could not find this one. 



P. 165. — I cannot answer this question. Is it 

 possible that he was thinking of St. Augustine ? 

 In the Confessions, i. 25., we find the expression 

 vinum erroris. 



P. 177. — No doubt Bacon had read the treatise 

 of Sallust quoted, but my impression is that he 

 thought the proverb had grown out of the line in 

 Plautus. 



P. 180. — I have searched again for " alimenta 

 socordiae," as it is quoted in the Colours of Good 

 and Evil, but cannot fix upon any passage from 

 which I can say it was taken, though there are 

 many which might have suggested it. One at 

 p. 19. of the Advancement, which I missed at first, 

 I have since met with. It is from the Cherson.y 

 p. 106. Thomas Markbt. 



PHOTOGRAPHIC CORRESPONDENCE. 



Test for a good Lens. — The generality of pur- 

 chasers of photographic lenses can content them- 

 selves with merely the following rules when they 

 buy. It ought to be achromatic, i. e. consisting 

 of the usual two pieces of crown and flint glass, 

 that its curves are the most recommended, and 

 that it is free from bubbles : to ascertain the latter, 

 hold the lens between the finger and thumb of the 

 right hand, much as an egg-merchant examines 

 an egg before a strong gas flame, and a little to 

 the right of it ; this reveals every bubble, how- 

 ever small, and another kind of texture like minute 

 gossamer threads. If these are too abundant, it 

 should not be chosen ; although the best lenses are 

 never altogether free from these defects, it is ou 

 the whole better to have one or two good-sized 

 bubbles than any density of texture ; because it 

 follows, that every inequality will refract pencils 

 of light out of the direction they ought to go ; and 

 as bubbles do the same thing, but as they do not 

 refract away so much light, they are not of much 

 consequence. 



I believe If a lens is made as thin as it safely 

 can be, it will be quicker than a thicker one. I 

 have two precisely the same focus, and one thinner 

 than the other ; the thinner is much the quicker 

 of the two. An apparently indifferent lens should 

 be tried with several kinds of apertures, till it will 

 take sharp pictures; but if no size of aperture 

 can make it, or a small aperture takes a very long 

 time, it is a bad lens. M. Claudet, whose long 

 experience in the art has given him the requisite 

 judgment, changes the diameter of his lenses often 

 during the day ; and tries occasionally, in his ex- 

 cellent plan, the places of the chemical focus : by 

 this his time is always nearly the same, and the 

 results steady. As he is always free in communicat- 

 ing his knowledge, he will, I think, always explain 

 his method when he is applied to. The inexpe- 

 rienced photographer is often too prone to blame 

 his lens when the failure proceeds more from the 

 above causes. The variation of the chemical focus 

 during a day's work is often the cause of disap- 

 pointment : though it does not affect the landscape 

 so much as the portrait operator. 



