256 



NATURE 



\yan. 28, 1875 



burial which was formerly practised among the Indians of North 

 Carolina. He states that in numerous instances burial-places 

 have been discovered where the bodies had been laid with the 

 face up and covered with a coating of plastic clay about an inch 

 thick. A pile of wood was then placed on lop and fired, consuming 

 the body and baking the clay, which retained the impression of 

 the body. This was then lightly covered with earth. 



Interesting additions to our knowledge of tlie fauna of the 

 Mammoth Cave have recently been made by Mr. F. W. Putnam, 

 of Salem, U.S., who, as a special assistant on theKentucky State 

 Geological Survey, of which Prof. N. S. Shaler is the director, 

 had great facilities extended by the proprietors of the cave, and 

 he made a most thorough examination of its fauna, especially in 

 relation to the aquatic animals. Mr. Putnam passed ten days 

 in the cave, and by various contrivances succeeded in obtaining 

 large collections. He was particularly fortunate in catching five 

 specimens of a fish of which only one small individual had here- 

 tofore been known, and that was obtained several years ago 

 from a well in Lebanon, Tennessee. This fish, which Mr. 

 Putnam had previously described from the Lebanon specimen 

 under the name of CJioIogastcr agassizii, is very different in its 

 habits from the bhnd fishes of the cave and other subterranean 

 streams, and is of a dark colour. It lives principally on the 

 bottom, and is exceedingly quick in its motions. It belongs to 

 the same family as the two species of blind fishes found in the 

 cave. He also obtained five specimens of four species of fishes 

 that were in every respect identical with those of the Green 

 River, showing that the river fish do at times enter the dark 

 waters of the cave, and when once there apparently thrive as 

 well as the regular inhabitants. A large number of the white 

 blind fishes were also procured from the Mammoth Cave and 

 from other subterranean streams. In one stream the blind fishes 

 were found in such a position as to show that they could go into 

 daylight if they chose, while the fact of finding the Clwlo^aster in 

 the waters of the Mammoth Cave, where all is utter darkness, 

 sliows that animals with eyes flourish there, and is another proof 

 that colour is not dependent on light. Mr. Putnam found the 

 same array of facts in regard to the crayfish of the cave, one 

 species being white and blind, while another species had large 

 black eyes, and was of various shades of a brown colour. A 

 number of living specimens of all the above-mentioned inha- 

 bitants of the waters of the cave were successfully brought to 

 ISlassachusetts after having been kept in daylight for several 

 weeks, proving that aU the blind cave animals do not die on 

 being exposed to light, as has been stated. 



We have received the Ainuiaire of the Belgian Academy for 

 1S75. It contains the usual useful information concerning the 

 organisation and work of the Society, the prizes it awards, list of 

 members, &c. The principal memoir is that of Quetelet, men- 

 tioned in Nature, vol. xi. p. 217, with a portrait ; there are also 

 memoirs, with portraits, of two other deceased members, Charles 

 Poelman, the comparative anatomist, and H. L. F. Partoes, the 

 architect. 



The additions to the Zoological Society's Gardens during the 

 past week include an Australian Cassowary {Casnayins australis), 

 new to the collection, from Australia, presented by the Marquis 

 of Normanby ; a Banded Cotinga (Cotiuga ciiula) and a Naked- 

 throated Bell-Bird (^ChasmorJtyiukus niidicollis), from Bahia, 

 purchased ; a King Vulture {Gyparchiis papa) from Buenos 

 Ayres, presented by Mr. M. Billinghurst ; a Bonnet Monkey 

 {Mtaicus iv.diatKs) and a Macaque Monkey (M. rynomolgus), 

 presented by Mr. H. Lumsden, a Rhesus Monkey (M. aythrais), 

 presented by Mr. W. de Winton, and a Bonnet Monkey, pre- 

 sented by Miss M. Hailes, all from India ; a Black-tailed Ante- 

 lope {.Namtragus nigrkaudaius) frpm West Africa, purchased. 



ON 



THE MUSCULAR MECHANICAL WORK 

 DONE BEFORE EXHAUSTION 

 IV/rUSCULAR exertion may be either dynamical or statical. 

 Dynamical work is generally intermittent, while statical 

 work is generally continuous in its action. The dynamical work 

 done by any muscle before exliaustion is easily measured in 

 kilogramraetres. Assuming the force exerted by any muscle to 

 be K', and if « be the number of times the force is exerted 

 through the distance /;, until exhaustion sets in, then the total 

 work, W, done before exhaustion, is 



]V=iohn (i). 



If, however, a weight, w, be supported on the horizontally 

 outstretched arm, then by the above formula the amount of 

 worlc is zero, although the arm soon tires out. In his " Principles 

 of Animal Mechanics" pp. 24 — 44, London, 1S73, Mr. Haughton 

 has attempted to estimate the statical work thus done by the 

 muscles of tire arm. Let w = the weight, a = weight of ann, 

 a = distance from centre of glenoid cavity to centre of weight, 

 and / = time in seconds before exhaustion. The muscles exert 

 a force capable of sustaining the weight of the loaded arm at its 

 centre of gravity. Let fi be a small arc, through which the arm 

 moves uniformly with an unknown angular velocity Tc in the 

 time t. Then, if -v is the distance from the centre of the glenoid 

 cavity to tlie centre of gravity of the loaded arm, we have — 



Total work = (s« + a) x 6 

 But since 



i'u + a) 



'(" -1} 



and = wt, we shall have^ 



Total work; = >■- a (w -|- -^^ ; (2). 



The v.ilues of ((7) and (a) are easily obtained by direct mea- 

 surement and weight. This formula (2) is, however, no better 

 than (i), for when is zero, ti' is also zero, and the work would 

 be notliing. Mr. Haughton has, however, used this formula, 

 assuming 6) = I, which value he has deduced from experiments 

 made by myself (Prin. of Animal Mech., pp. 475 — 7), and 

 published in the Scliool Laboratory, 1S71, vol. i. p. loS.* The 

 experiments were conducted as follows : — ■ 



A weight u< = yoo kilos, was lifted from a vertical to a hori- 

 zontal with the shoulder, in a varying time t. At the instant the 

 weiglit reached the horizontal, the muscles were relaxed, and the 

 weight allowed to drop, being caught on a cushion attached to 

 the leg. The intervals of work and rest, t, were in all cases 

 equal. (I intend to repeat these experiments, making the interval 

 of rest constant). Mr. Haughton has repeated my experiments, 

 and has deduced the formula — 



At , . 



» = — -:rr„ (3). 



(2 to\ ''t^ 



where // is the number of lifts before exhaustion, 

 tions for my right arm are given below. 



rt'per cent. 



22 '2 

 22-8 

 217 

 l8-2 

 15-5 



13-8 

 12-6 

 9-4 



17 

 i-g 

 13 

 2-8 

 3« 



The values of the constants in (3) as obtained by Mr. Haughton 



are, ./ = 30-4 and — = o"656. Substituting these values, and 



the proper values of t in (3), and we have n (calc). Column 

 d is the difference in per cent, of >i (obs. ) Each value of « obs. 

 is a mean of four determinations. The probable error of this 

 mean in per cent, of //(obs.) is given in column e. The experi. 



* These experiments were merely published as a preliminary, in order 

 ihat I might pursue the investigation at my leisuae. 



