NATURE 



\ March lo, 1881 



that the i-lime-glands were much less developed in the males than 

 in the females. 



The structure of the female organs in our Caracas species 

 agrees pretty well with Prof. Hutton's drawings {Ann. and 

 Mag. of Nat. Hist.y iv. ser., vol. l8, pi. xvii., fig. 8) ; but I am 

 not prepared to accept his interpretation. The following sketch 

 will give an idea of what I saw. 



Moseley's Fig. I on pi. Ixxiv. is very different from the shape 

 of the ovary in our species ; nor can I well understand the exist- 

 ence of ova on the outside of the ovary as they appear in Ins 

 drawing. The ovary in P. Edwardsii is rather loni;, and 

 abundantly covered by fine tracheal tubes, with the exception of 

 a narrow zone close to the branching out of the oviducts. I 

 could not satisfy myself as to its being div-ded by a septum, nor 

 could I find any ova in it ; most likely it is not now tlie riL;ht 

 time. At a very short distance from the beginning of the ovi- 

 ducts there is a kind of obtuse caciim on each of them, which 

 is followed by a spherical body covered by tracheal tube<. 

 These bodies are the organs described by Prof. Hutton as testes. 



There is however in our species no trace of what he tal<es for 

 vasa defi'rtntia, the spherical body adhering directly to thf ovi- 

 duct. Its wall is of considerable resistance, and bursts only 

 under great pressure, giving is^ue to an immense number of thin 

 rod-like corpuscula, which soon after begin to move slo«ly in the 

 surrounding water. They are of course spermatozoa which have 

 lost their nuclei, and the spherical body can therefore be n< .thing 

 else but a rice^taciiUim seniinis. 



The oviducts of three specimens which I dissected contained 

 very few embryos ; in one there was only one in each oviduct, in 

 the others there were two. They were fully developed, and 

 occupied tlie part of the oviducts close to the vulva. It would 

 appear from this that the time of reproduction is now almost 

 over ; further observations will show whether there is really such 

 a periodicity in our sijecies. 



It is probable that the oviducts of P. Edwardsii never pre-ent 

 the shape of strings of sausages, as seen by Mr. Moseley in P. 

 CapL'Hsis, the embryos being so considerably larger. 



Animals thrown alive into alcohol pour forth from their slime- 

 glands first the viscid substance contained in these ; then there 

 comes out a slightly reddish matter, which dissolves in the 

 alcohol, giving it the same colour. 



With respect to all other points I can only confirm Mr. 

 Moseley's statements. 1 keep alive a colony of Peripatus of 

 both sexes in the hope to have once a chance to observe the 

 copula. 



I cannot conclude these remarks without confessing that I am 

 not at all quite sure whether our Perifatiis is really P. Edwardsii, 

 as the figure of this species in Nicholson's *' Manual of Zoolo^^y " 

 (Stli edit. p. 315), which is s.aid to be after Grube, does not 

 agree well with my living specimens. Gnibe's original paper I 

 cannot consxilt here. It may be however that he made liis 

 drawing from a contracted alcoholic specimen. A. ERNsr 



The University, Caracas, January 16 



ACOUSTICS IN CHINA 



'T'HE following letter to Prof. Tyndall has been sent to us for 

 publication by the writer, Mr. Fryer. It will be seen that 

 a really scientific modern correction of an old law has singularly 

 turned up from China, and has been substantiated with the UiOst 

 primitive apparatus. Dr. \V. H. Stone, to whom the letter lias 

 been submitted, has kindly appended a note. 

 To Prof. Tyndall, LL.D., F.R.S., &c. 



Dear Sir, — My friend Mr. Hsu has brought some interesting 

 facts relating to acoustics before my notice. .\s he is the fatlier 

 of the native official who translated with me your work "On 

 Sound," and as he refers particularly to that work, I venture t'j 

 forward you a translation of his remarks, in the hope that you 

 will satisfy his mind on a subject in which he takes such deep 

 interest. He says : — 



" In ancient Chinese works on music it is stated that strings 

 or pipes produce an octave or twelve semitones higher or lower 

 by halving or doubling their length. 



" In a work written during the Ming dynasty by Chen-toai- 

 yoh it is stated that this rule will only hold good with strings, 

 but not with open pipes such as the flute or flageolet. 



" Some years ago I tried to investigate the cause of this dif- 

 ference and its exact amount. A round open trass tube, say 

 nine inches long, gave a certain note by pressing the end of it 

 against the upper lip and blowing through an embouchure made 



there. Cutting off half the tube, the remaining four and a half 

 inches would not sound the octave ; but by cutting off half an 

 inch more, thus leaving four inches in length, the octave was 

 sounded accurately. This experiment was tried on tubes of 

 various lengths and diameters with a similar result, viz. that 

 four-ninths of the length always sounded the octave more or less 

 exactly. Looking at a foreign keyed flute I noticed the same 

 principle carried out in the arrangements for producing octaves. 

 I could not however see the reason why open pipes should not 

 follow the ^ame rule as strings and closed pipes. 



"When I read the translation of Prof. Tyndall's treatise 

 'On Sound,' I was surprised to find the old Chinese idea 

 strictly maintained. It says (p. 214) : 'In both stopped and 

 open pipes he number of vibrations executed in a given time is 

 inversely proportional to the length of the pipe,' &c. According 

 to this, as the octave of any note has to execute exactly double the 

 number of vibrations in a given time, an open pipe ought to be 

 exactly halved to make it sound an octave higher. This I have 

 shown to be erroneous by my experiments. 



" Fearing that I have misunderstood the English professor's 

 meaning, I beg that he may be written to on this subject, and 

 that my doubts may be thereby cleared up. What I want to 

 know is the exact jsroportion in length that exists between any 

 open pipe and a pipe of similar diameter sounding its octave 

 higher. Also the exact proportions in Ien;'th for each of the 

 open pipes sounding the twelve semitones which form a scale of 

 one octave. If the length forming the octave in open pipes 

 does not agree with the length for strings or closed pipes, then 

 the lengths of all the pipes giving intermediate notes must al.so 

 differ. How are tlese lengths to be calculated? Can they be 

 expressed by any mathematical curve or formnla ? Why does 

 not the same rule hold good for open pipes as for strings or 

 stopped pipes? I have a theory of my own, but I do not feel 

 sufificient confidence in myself to make it public until I have 

 bestowed more thought and attention upon it. In the meantime 

 I shall be glad if any foreign scientists can enable me to under- 

 stand this interesting and important subject. The theory and 

 practice of music in China has gradually become vitiated through 

 errors in the construction of musical instruments, and I am 

 therefore desirous of having a scientific basis upon which a 

 reformation may be effected." 



There is no treati-e on music or acoustics that I can find which 

 throws any light on these interesting questions, and I shall 

 therefore deem it a great favour if you will direct me to any 

 work that will enable me to satisfy the eager inquiries of my 

 native friend. 



I send by book-post a pamphlet for your kind acceptance, 

 containing an account of the Department for the Translation of 

 Scientific Books at the Kinagnan Arsenal. You will see that 

 your "Notes on Light " are now published in Chinese. A copy 

 will be forwarded to you shortly. Vour " Heat a Mode of 

 Motion " I hope to begin to translate at no very distant time. 

 Your "Notes on Electricity" in t hinese will be published 

 shortly. 



I remain, dear Sir, yours faithfully, 



Sh.anghai, June I, iSSo John Fryer 



Nmember I'^th, 1880 

 P.S. — I have sent a copy of this letter to the Editor of 

 Nature, and shall feel greatly obliged if you will forward your 

 reply, if any, to him for publication, — ^J. F. 



Mr. Fryer is perfectly correct in his observations. You will 

 find the explanation and formula needed at p. 167 of my little 

 book on Sound, under the heading "Correction of Bernouilli's 

 Law." "It has long been known," I there say, "that if an 

 open pipe be stopped at one end its note is not exactly an octave 

 below that given by it when open, but somewhat less, the interval 

 being about a major seventh instead of an octave." 



Then follows the mathematical statement, from which the 

 corrections needed by Mr. Fryer could easily be obtained. M. 

 Bosanquet's excellent experimental investigation of the subject is 

 briefly described. His results give the correction for the open 

 end of the pipe .as '635 of radius of pipe, and '59 r for the 

 mouth. Mr. Bosanquet remarks that in Bernouilli's theory the 

 hypothesis is made that the change from the constraint of 

 the pipe to a condition in which no remains of constraint are 

 to be perceived takes place suddenly at the point where the wave 

 system leaves the pipe. It is however evident that the diverg- 

 ence which takes place may be conceived of as sending back to 

 .he pipe a senes of reflected impulses, instead of the single 



