302 
SCIENCE. 
been distilled several times can remain exposed to the air 
for six or eight days without the slightest augmentaflon 
of resistance, in regard to the needle, being apparent. 
Besides, in the measures taken with distilled water, the 
entire preparation of the experiment from the moment 
when the liquid was poured into the capsule until the 
needle, was left to itself, occupied but five minutes ; then 
during the ten partial measures afterward effected, no 
increase of resistance was observable. Could particles 
of dust floating about in the atmosphere produce an 
effect during those five minutes ? Is it admissible ? In- 
deed, M. Hagen has shown us conclusively that the 
superficial tension of distilled water decreases perceptibly 
when the liquid is exposed to the air ; but this diminution 
is gradual and continued, and in order to produce any 
visible effect requires several hours The peculiar fact 
M. Hagen describes, therefore, appears to me to bear no 
relation whatever to the resistance shown to the needle’s 
movements; and inasmuch as air on the other hand, 
exercises no chemical action upon distilled water, and 
moreover as we are "unable to invoke the influence of 
particles of atmospherical dust, we are led to attribute 
the fact established by M. Hagen to a cause arising from 
the interior of the liquid. 
Now, in reference to the actual state of the case, I 
shall say again that it is useless to have recourse to a 
coating of dirt whose existence we cannot account for, 
and also that it is much more simple to admit the pres- 
ence of an atomic organization peculiar to the superficial 
layer of the liquid. 
As far as M. Van der Mensbrugghe’s theory is con- 
cerned, M. Marangoni expresses himself in the following 
manner ; 
“ The mass of the liquid effectually diminishes the 
variations of temperature produced upon the surface, 
which, in its turn, also decreases the variations of ten- 
sion ; in ordinary cases the latter are but trifling when 
compared with the variations attributed to dirt.” 
According to this remark, we should believe that the 
surface of the saponaceous solution, which, M. Marangoni 
states, possesses an undeniable coating of dirt, resists 
the movements of the needle more forcibly than the dis- 
tilled water which could have hardly any dirt on its sur- 
face. In my experiments however, directly the opposite 
of this has occurred. The ratio of time required for the 
needle to describe an angle on the surface and beneath 
it when distilled water was used was, i, 92, while when 
soap was used it was but 1, 82. 
M. Van der Mengsbrugge’s theory certainly deserves 
some attention in regard to the phenomena >n question ; 
but owing to the above remark of M. Marangoni, and 
the considerable dimension of the needle, relatively 
speaking, we may be permitted to doubt that any notable 
effect can result from it. Besides, if it did, we should 
find it again in those liquids of weak tension which do 
not produce bubbles, that is to say, alcohol, spirits of 
turpentine, olive oil, etc.; at least we should be able to 
observe a feeble rotation of the entire surface ; now, this 
is by no means authenticated. 
Finally, before attributing these phenomena to any 
other cause than that of a peculiar viscidity of the outer 
coating, it would be necessary to refute those arguments 
which have led me to the conclusion that the superficial 
coating of liquids possesses more atomic mobility than 
the interior portion. M. Marangoni is perfectly silent in 
regard to this part of my work. 
After this examination of M. Marangoni’s theory how- 
ever, I consider myself justified in maintaining my opinion; 
but I forego all ulterior discussions referring to the sub- 
ject, and leave all those physicists who may be interested 
in the question, to compare for themselves M. Marang- 
oni’s writings with mine, and to try to discover, if pos- 
sible, which of us is right. 
ON THE STRUCTURE OF THE ORANG 
OUTANG. 
By Hbnry C. Chapman, M. D. 
From the paper on this subject in the Proceedings of 
the Academy of Natural Sciences, of Philadelphia, we 
take the following facts: 
The subject dissected was a young male Orang Outang 
( Simia Satyrus), about three years old. The first thing 
to strike Dr. Chapman was the length of the upper ex- 
tremity, it being three inches longer than the lower one, 
agreeing nearly in this respect with the Gorilla, the differ- 
ence in the extremities of that animal being 2/4 inches, 
whereas in the Chimpanzee a difference of 1 y inches onlv 
was found. The foot in the Orang, however, was ]/ z 
inch larger than the hand, whereas in the Gorilla the hand 
was l / z inch larger than the foot ; in the Chimpanzee the 
difference in this respect was y%- in. in favor of the foot. In- 
deed, the distinctness of hand and foot superficially is 
more marked in the Gorilla than in the other anthropoids. 
The same facial muscles are found in man and the Orang 
Outang, with the exception that there is but one zygoma- 
ticus, possibly corresponding to the zygomaticus minor of 
man. The facial muscles, however, are not differentiated as 
in man, rather hanging together. The upper extremity of 
the Orang, in its muscles, differed essentiallyfrom that of 
man in the absence of the flexor longus pollicis, and ex- 
tensor primi internodii pollicis and in the presence 0 j- 
the additional tendons to the ring and middle fingers • 
The Orang agreed with the Gorilla in not having a 
flexor longus pollicis, but disagreed with it in having the 
pronator radii teres, arising by two heads in the presence 
of a palmaris longus, in the additional tendons for ring 
and middle fingers, and in not having the extensor primi 
internodii pollicis. 
As compared with the Chimpanzee, the Orang agreed 
in reference to the pronator radii teres and palmaris 
longus, but in the absence of the flexor longus pollicis as 
a slip from the profundus, and in the presence of the ad- 
ditional extensor tendons it differed. 
Dr. Chapman differed from Bischoff, Owen, Huxley 
and others, in seeing no essential difference between the 
scansorius, of Traill, and the glutaeus minimus in man, 
an opinion, it appears, which had been previously ex- 
pressed by Prof. Barnard in 1876. 
The leg and the foot of the Orang, as compared with 
man, differed in the absence of the peroneus tertius, plan- 
taris, flexor longus hallucis and transversus pedis, in the 
fibular origin of the soleus, and in the presence of the 
external origin of the accessorius only, in the distribution 
of the perforating and perforated tendons of the toes, in 
the interossei, and in the presence of an opponens for 
the big toe. In this latter respect, the Orang differs not 
only from man, but from all the other monkeys and 
anthropoids, the foot having a very hand-like appearance, 
as compared with that of the Gorilla and Chimpanzee. 
The foot of the Orang differs further in the absence of a 
special flexor for the big toe. This is supplemented, to 
a certain extent, by the opponens, and in a partly devel- 
oped accessorius. 
If Professor Huxley’s canon can be accepted that the 
distinction between a hand and a foot consists in the latter 
possessing tarsal bones, the peroneus longus and brevis, 
the short extensor and short flexor muscles, then the pos- 
terior extremity of the Orang terminates in a foot. 
Dr. Chapman, however, appeared to think that the dif- 
ference between the hand and the foot in Man, the Gorilla, 
and Chimpanzee, and the lower monkeys, is greater than 
that observed between the corresponding members of the 
Orang. 
It is usually stated that the uvula is absent in the Orang, 
and on looking into the mouth, at first sight this appears 
to be the case, as it does not hang down as in man, be- 
tween the pillars of the fauces. Nevertheless, Dr. Chap- 
