NOVEMBKK 30, 1883.] 



SCIENCE. 



711 



wholly in black, and narrow bands of some brij;lit 

 metal are placed down liis arm, tliigh, and leg, follow- 

 ing precisely the direction of the bones of these parts. 

 This arrangement allows us to easily increase ten- 

 fold the number of images received in a given time 

 on the same plate : hence, instead of ten photographs 

 a second, we can obtain one hundred. For this, the 

 rapidity of rotation of the disk is not altered ; but, in- 

 stead of one opening, there are ten, eiiually distributed 

 on the circumference. One of these openings must 

 have a diameter twice that of the others. The result 

 is a much larger size for one of the images; and this 

 renders the estimation of the time easy, and also fur- 

 nishes data to compare the movements of the lower 

 and upper limbs. The images obtained under these 

 circumstances are so close, that one is present, as it 

 were, at all the successive changes of place of the 

 limbs and body. Thus, in fig. 8, between two suc- 

 cessive touches of the ground by the right foot, there 

 are twenty-one different positions of the lower limb. 

 As the foot meets the ground, the knee is bent per- 

 ceptibly; then it straightens as the foot, resting on the 

 toes, prepares to leave the ground. After the raising 

 of the foot, the knee bends again, and the leg forms 

 with the thigh a right angle; then it gradually be- 

 comes straight, and the sole of tlie foot, which was at 



The few examples just given sufficiently explain the 

 method, and show its exactness. For a complete 

 study of human locomotion, photographs under the 

 most diverse ciicumstanccs must be obtained. The 

 subject must be photographed not only from the side, 

 but also from the front and rear, in onler to show the 

 lateral oscillations of the different parts of tlie body. 

 Finally, after studying the mechanism of the various 

 motions produced in walking or rimning, the final re- 

 sult — the more or less rapid transportation of the 

 man — must be studied, either as he walks freely, or 

 as he bears or draws a burden. 



Tliese researclies have a practical interest, even as 

 those having for their object the determination of the 

 product of macliines, and the most favorable con- 

 ditions for this production. Experiments in regard 

 to tliis are in process; and it is with this object in 

 view that the circular course with telegraphic signals, 

 to note the phases of the walking or running, has 

 been established. 



first in a vertical plane, is apparently parallel to the 

 ground which it touclies for some time before it rises 

 again. The scale at the bottom of the figure shows 

 that the total length of the step was 2.6 metres. The 

 chronograph was not used in this experiment, but we 

 may estimate the number of images at about sixty 

 a second. The movements of bending and extending 

 the fore-arm are obtained in the s.ame manner as 

 those of the leg. The turnings of the head are ex- 

 pressed by the undulatory motion of a bright point 

 placed on a level with the ear. In short, the diminu- 

 tions and the accelerations of each part are expressed 

 by the crowding or separation of the images. To 

 ascertain the corresponding positions of the arm and 

 leg at a given instant, we take for data every fifth 

 figure, which is larger than the others. These images 

 are formed at the moment of passage before one of 

 the larger openings; and they correspond, therefore, 

 to the same instant of time. This is not the phace to 

 analyze in detail the various types of locomotion. 



THE FUNDAMENTAL CATALOGUE OF 

 THE BERLINER JAHRBUCH. 

 A VEKY important comparison by Dr. Auwers, of 

 the fundamental catalogue of the Berliner jahrbuch 

 with those of the Nautical almanac, 

 the Connaissance des tempn, and the 

 American ej)hemeris, appears as a 

 supplement to the JahrJiuch for 1884; 

 and the following abstract of it is 

 given. The year 1883 is the first in 

 which such a comparison is possible. 

 The Berliner jahrbuch contains at 

 present, and will contain for the fu- 

 ture, 450 stars whose apparent places 

 are given, and 172 stars for which 

 only mean places are printed; i.e., 

 622 in all. The places of these stars, 

 both in K. A. and Dee., depend strict- 

 ly on the system of the Fundamen- 

 tal catalogue of the Astronomische 

 f/exellschaft (publ. xiv. ). They lie 

 between the north pole and — 31°.3 declination. 



The American ephemeris contains the mean places 

 of 383 stars, for 208 of wliich ephemerides are given: 

 44 of these stars lie south of —31°. The Nautical 

 almanac has 197 stars (15 south of —32°), and ephem- 

 erides are given for all. The Connaissance des iemps 

 has 310 stars between the north pole and — 70°, and 

 gives an ephemeris for each. 



Dr. Atiwers's account of the sources from which the 

 star-places of the various almanacs are taUen we omit. 

 It shows how v.arious these are. 4.")0 stars have 

 ephemerides in the Jahrbuch ; 140 stars (mostly south- 

 ern) wliich h.ave ephemerides in the three other alma- 

 nacs are not contained in the Jahrbuch. 



A table is given in Dr. Auwers's paper, showing the 

 comparison between each star of each almanac and 

 the./a/ir6i(e/i. From this table the elements by which 

 the catalogue of each almanac can be reduced to the 

 system of the Jahrlmrh are di'dneed. A subsequent 

 table gives the two ridnclions which must be added 



