The Optical Lantern and Cinematograph Journal (Nov 1904-Oct 1905)

Record Details:

Title:
The Optical Lantern and Cinematograph Journal
Date:
Nov 1904-Oct 1905
Publisher:
London, E.T. Heron
Volume:
The Optical Lantern and Cinematograph Journal (Nov 1904-Oct 1905)
Leaf #:
000187
Language:
English
Subjects:
Motion Pictures, Film Industry Trade Magazine
Collection:
United Kingdom and Global Cinema
Contributor:
Media History Digital Library
Sponsor:
Media History Digital Library
Coordinator:
Media History Digital Library
Date Added:
December 14, 2023
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THE OPTICAL LANTERN AND CINEMATOGRAPH JOURNAL. '75 just visible among the trees on the sky line. It was a nasty object, that is, its surroundings made the stereoscopic effect difficult to get. Five readings of this were taken, and the middle one. of them — which has always been found far more reliable than the mean — gave the distance 10,740 yds., as measured in the Ordnance Map, correct to 100 yds. in 10,000. This gives 7 ins. on a bad object at very long range indeed. Another case was at Gibraltar — same observer. His readings on the corner of a castle were 2147, 2149, 2149, 2147, 2147, 2145 Here, then, we have five successive readings, the maximum difference being 4 yds., which, with eight magnifying power at 2.000 yds., means an angle of 2'.s sees, as maximum error. His note on this says : — " The scale of instrument at this range does not permit of accurate reading to less than 5 yds., but knowing that the greatest possible precision was wanted, I estimated the values of very slight differences in a set of almost identical readings. I might have entered them all as identical except the last." When he had finished he was told by the R.E. Captain, before whom he was working, that the distance was 2,451 yds. He thereupon checked his Range-Finder autonomously, found it perfect, and asked to have the R.E. measurements checked, as they were certainly wrong. They were re-checked, and the actual distance was found to be 2,1457 yds. Light, atmosphere, and object were no doubt perfect ; but that merely means that there were no opposing elements, nor that there was any assistance from any other source. The distance was measured repeatedly and accurately by the stereoscopic power, and that alone; that reduces Helmholtz's 1 minute to about 3 seconds. TABLE I. Tests at 7 ft. and 23 ft. 6 in. by two observers. Wax matches with red heads level with each other and with the eye. One match can be pulled towards or away on a slide, but nothing but the matches are visible. + means the movable match was set too far and met versa ; " o "' means less than J mm. Distance 7 ft. Distance 2 3 ft. 6 in. 1 mm. = 23 sees. 1 mm. = -28.. F. C. F. C. 5" IO" 3 '36 + 3 36 0 + 2'5 1 20 -28 2-5 + 2-5 + 2 '24 + 672 + -25 + 1.25 + -84 + -28 5 + 375 o + 3'& + '5 + 10 + -56 + 3 '92 + 5' 0 I-20 + 1680 + 2-5 0 -s4 + 7-«4 0. + 7'5 + 2' 80 5' 0 + 3 '92 Mean 2-6" 37" Mean 17" 4'2" Al. Mn. -9" + 2711 Al. Mn. '37' 4-2" TABLE II. Tes ' ON Various P EOPLE AT 7 Fr. Age. Mean M IX. I D H. 06 2'3" 3' 6" Engr. Well-known tennis player 2 E. C. 3° 27 5-4 Sol i c itor. Good billiard player 3 B. 4'5 9 Engin< er G 0 0 d billiard player 4 A. T. 46 5-1 9 Skilled Observer 5 T. B. 9 5-2 9 Board-school boy 6 M. 25 5-8 9 Physical Laboratory assistant 7 M. H. 35 5-8 9 Lady. Very good tennis player 8 J. R. 47 7'2 14 Physical laboratory assistant 9 E. 46 9 11 Lady. Good tennis player 10 C. 45 9i '3 Skilled observer, after good practice with R.E. 11 S II. 10 10 22 Board-school boy 12 R. R. 45 11 36 Engineer ■3 Mi. 20 1 1 18 Physical laboratory assistant M II. O. 5 11 45 Board -school boy «S g 9 u-6 27 Board-school girl 16 O. Ch. 70 '5 22 Engineer. Skilled observer 17 T. R. 6 I5-S 31 Board -school boy iS Res. 5° 19 3' Chemist 19 C. P. 4 22 36 Board-school boy 20 Hadl. 35 40 6S Engineer -? -s -?~ Correspondence ADVERTISEMENTS ON THE CLOUDS. Sir, — Some time ago a firm in London projected words or advertisements with a lantern or searchlight on the clouds or atmosphere. Could you give me any information about it, or the name of the firm that supplied the apparatus. — Yours, etc., J. W. HAVWARD, 122, Yorkshire Road, Rochdale [Our correspondent doubtless refers to apparatus invented by Mr. Eric Bruce, called the atrial graphoscope. We do not know this gentleman's address, perhaps one of our readers can supply it. Ed.] **> Sir, — Please forward me the Lantern Journal from Dec. issue, for which find enclosed 5s. I have an English book, " Living Pictures," by H V. Hopwood, dated 1S99. Would you kindly inform me if any later books have been issued on the subject and where obtainable. — Yours, etc., HERBERT FINLAY, Blyth St., Brunswick, Victoria, Australia. [Animated Photography, the A B C of, by Cecil M. Hopworth. No. 14 of the "Amateur Photographer," Is., of Messrs. Hazell, Watson & Viney, Ltd., 1, Creed Lane, London, E.C. This little work will be. useful to you as it has lately been supplemented with contributions by Hector Maclean — Ed. ]