348 



NOTES AND QUERIES. 



[No. 206. 



Unfortunately these subjects are again forced 

 upon 113, and a reference to some of the books I 

 have cited will enable gentlemen who are curious 

 upon the point to judge for themselves in the 

 jnatter of the present agitation of "Justice to 

 Scotland." , J- 0- 



On May 5, 1686, M.Claude's account of the 

 Massacre of St. Bartholomew was burnt in the 

 Old Exchange, " so mighty a power and ascendant 

 here had the French ambassador." (Evelyn's Me- 

 „ioi7-s.) John S. Burn. 



PHOTOGRAPHIC CORRESPONDENCE. 



Stereoscopic Angles. — As I presume that Mr. 

 T. L. Merritt is, like myself, only desirous of 

 arriving at truth, I beg to offer the following 

 reply to his last communication (Vol. viii., 

 pp. 275-6.), in which he misinterprets some ob- 

 servations of mine upon the subject in question. 



With regard to the distance quoted by _rae of 

 2^ inches, "l look upon it as the same thing as 

 intended by Mb. Merritt — that ij, the average 

 distance between the centres of the eyes ; and it 

 amounts simply to a difference of opinion between 

 us ; but, so far as that point is concerned, I am 

 quite ready to adopt 2i inches as a standard, al- 

 though I believe that "the former is nearer the 

 truth : however, I require more than a mere asser- 

 tion that " the only correct space for the cameras 

 to be apart is 2| inches, and this under every 

 circumstance, and that any departure from this 

 vinst produce error." I quote verbatim, having 

 merely Italicised three words to point my meaning 

 more clearly. An object being 5 feet distant, and 

 another at 10 feet from the observer, a line be- 

 tween the eyes will subtend a very much larger 

 angle in the former than in the latter instance : 

 hence the inclination of the axes of the eyes is the 

 chief criterion by which people with the usual 

 complement of those useful organs judge of proxi- 

 mity : but if half a dozen houses are made to ap- 

 pear as if 10 or 12 feet distant (by means of the 

 increase of the angle between the points of form- 

 ation of the pictures), while the angle which each 

 picture subtends is relatively small; it is clear 

 that both eyes will see in relief at a short distance 

 half a dozen houses in a space not large enough 

 for a single brick of one of them, and, consequently, 

 the view will appear as if taken from a model. 

 Mr. Merritt will object that an erroneous effect 

 is produced; If he will refer to my statement 



derson received the tlianks of the Scottish parliament, 

 as well as some pecuniary reward. (Chalmers' Life of 

 Euddiman.) Tlie authors of these books having made 

 out a case which was adopted as the national one, it is 

 nowise surprising that they should hand over Drake 

 and Attwood to the hangman for attempting to de- 

 molish it. 



(Vol. viii., p. 228.), he will find that it is precisely 

 what I admitted; and he appears to have over- 

 looked the p7-oviso attached to my next observ- 

 ation (judging by his comment thereon), so 1 shall 

 make no farther remark upon that point, beyond 

 inquiring why the defect he is content to put up 

 with is called a trifling exaggeration, while that 

 Avhich is less offensive to me is designated as absolute 

 deformity and error ? Persons with one eye are 

 not good judges of distance, and this may be easily 

 tested thus: — Close one eye, and endeavour to 

 dip a pen in an inkstand at some little distance 

 not previously ascertained by experiment, with 

 both eyes open ; it will be found far less easy than 

 would be imagined. One-eyed people, from habit, 

 contrive to judge of distance mainly by relative 

 position, and by moving the head laterally cause a 

 change therein : to them, all pictures are, to an 

 extent, stereoscopic. 



I am really amazed that my advocacy of the 

 radial, instead of the parallel, position of tha 

 cameras should have been so misunderstood. 

 Surely, it cannot be seriously asserted that the 

 former will produce two vanishing points, and the 

 latter only one ? And as to the supposition con- 

 nected with the boy, the ass, and the drum, a 

 camera that would produce the effect of showing 

 both sides of the ass, both legs of the boy, and 

 both heads of the drum, icith a movement of only 

 2^ inches, whether radially or parallel, would in- 

 deed be a curiosity. But if the motion of the 

 camera extended over a space sufficiently large to 

 exhibit the phenomena alluded to, then it would 

 confirm what I have before advanced, viz. present 

 the idea of a small model of the objects, which 

 could be so placed as to show naturally these very- 

 effects. 



That the axes of the eyes are inclined when 

 viewing objects, is readily proved thus : — Let a 

 person look across the road at any object — say a 

 shop-window ; but stand so that a lamp-post near 

 him shall intervene, and be in a di7'ect line between 

 the observer's nose and the object viewed. If he 

 be requested to observe the post instead of the 

 distant object, the pupils of his eyes will be seen 

 to approach one another; and on again looking 

 to the distant object, will instantly recede. The 

 range of vision Is another point that appears to be 

 misunderstood, as we are differing about words 

 instead of facts. The column Is an Illustration 

 that will exactly suit my views; for I call the 

 range of vision the same if taken from side to side 

 of the column, although It is perfectly true that 

 the tangents to the two eyes differ by the angle 

 they subtend : but certainly Ma. AVilkinson's case 

 (Vol. viii., p. 181.) of seven houses and five bathing- 

 machines In one picture, and five houses and eight 

 machines In the other, illustrates an instance where 

 the range of vision is not the same ; but I contend 

 that the stereoscopic effect Is then confined to five 



