March 29, 1877] 



NATURE 



475 



The most striking peculiarity of our fourth group of 

 Gentiana is the sensibility of their flowers to the in- 

 fluence of the weather, which is apparently connected 

 with the senHbility of their natural fertilisers to the 

 same influence. The following observation clearly shows 

 that different species differ widely in this sensibility, even 

 when growing in the same locality. On the Piz Umbrail, 

 July 16, 1874, I had collected some plants of Gentiana 

 bavarica, var. imbrica/a, and of G. verna, and put them 

 in my sleeping-room in the Quarta Cantoniera, upon a 

 plate filled with water. The next morning, at half-past 

 four o'clock, I found the flowers of G. bavarica already 

 opened, those of G. verna still closed. I placed the plate 

 outside the window, where the intensity of light was at 

 least as great, but the temperature much lower, and all 

 the opened flowers began twisting. After they had 

 closed, I brought them back into the room, and they 

 opened again. Repeating this trial from half-past four to 

 half-past six o'clock, I saw them two or three times 

 closing and opening again. Gentiana verna, standing 

 upon the same plate, during this time, had not yet opened 

 a single flower. 



From this observation, the further prosecution of which 

 was prevented by my departure, it is obvious (i) that the 

 opening of the flowers of these species of Gentiana is caused 



YxQ, 115. — Pedigree of the species of Gentiana of Germany and Switzerland. 



by heat, not by light ; (2) that G. verna requires a higher 

 temperature for opening than G. bavarica, var. imbricata. 

 Possibly this is one of the causes which makes G. verna 

 descend into sub-Alpine and low lands, whilst G. bavarica 

 is confined to the Alpine region. 



Comparing the present group with the foregoing ones, 

 we need hardly doubt that it is most nearly allied to 

 our second group, from which it differs only by the nar- 

 rowness of the corolla, by the further development of the 

 folds between the petals, and in connection with this by 

 their greater sensibility, and by the lobes of the stigma 

 being dilated. Gentiana prostrata, agreeing in every other 

 respect with our fourth group, has as yet retained the 

 two twisted stigma-branches, and therefore may be con- 

 sidered as a connecting species between the second group 

 and the fourth, which is descended from it. 



Summing up the above relations between the species of 

 Gentiana of Germany and Switzerland, we obtain a pedi- 

 gree like Fig. 1 1 5, in which the signification of the lettering 

 is as follows : — 



{a) Hypothetical ancestral form with fully open flowers, 

 twisted stigma-branches, diverging stamens, and honey 

 gecreted at the base of the flower in the angle between 

 the base of the pistil and the corolla. From this an- 

 cestral form we see two branches b and c descend ; b 



with the nectary confined to the base of the pistil, 

 c with nectaries at the base of the corolla. From the 

 branch c has developed the sub-genus Entotricha Froelich 

 {d), containing six species : — G. campestris, gernianica, 

 amarella, obtusifolia, tenella, and nana, adapted both 

 to Apidas and to Lepidoptera. Of the branch b an 

 original form, G. lutea (J?), has been preserved, acces- 

 sible to insects of all orders, but from the same branch 

 has descended the large sub-genus Ccelanthe Froelich {e), 

 containing eleven species : — G. punctata, pannonica, pur- 

 purea, cruciata, asclcpiadea, Pfieumonanthe, Ficelichii, 

 Jri^ida, acaulis, excisa, and ciliata, all adapted to humble- 

 bees. One branch of this sub-genus {e), by narrowing 

 the corolla, perfecting the folds between the petals, dilat- 

 ing the stigma-branches, and thus adapting the flowers 

 to Lepidoptera, has further developed the sub-genus 

 Cyclostigma {g), containing seven species : — G. bavarica, 

 verna, (estiva, imbricata, pumila, utriculosa, and nivalis. 

 As a link between the ancestral sub-genus [e) and the 

 derived subgenus G., has been preserved G. prostra a {/}. 

 Lippstadt Hermann Muller 



RECENTLY PROPOSED IMPROVEMENTS IN 

 MUSICAL INTONATION 



THE harshness of the present system of tuning has 

 been a source of constant complaint since it was 

 first introduced, about a century and a half ago. But of 

 late years several more or less practical attempts have 

 been made to overcome this defect without interfering 

 with the quality of our musical tones. Instruments with 

 fixed tones, as the organ, piano, and harmonium, lead 

 voices, and the inalterable quality of vocal tone has there- 

 fore to be constantly kept in view. The instruments 

 exhibited in the Lozm Collection of Scientific Apparatus 

 at South Kensington are enough to show both the objects 

 aimed at and the nature of the mechanical appliances by 

 which it is hoped they may be more or less reached. It 

 is difficult to give an intelligible account of them within 

 the compass of an article, but Dr. Stone's two lectures ^ 

 and Mr. Bosanquet's more recent work * will supply details 

 and figures. 



On examining musical tones generally ,3 we are led to 

 the conclusion that the first requisite is to have a succes- 

 sion of notes forming perfect Octaves, Fifths, and major 

 Thirds, that is, making numbers of vibrations which the 

 air executes during the same length of time in the ratios 

 1:2, 2:3, and 4 : 5 respectively. An examination of 

 prevailing systems of modulation, has shown* that a 

 strict fulfilment of this condition would require 117 notes 

 to the Octave — a mechanical impossibility on any instru- 

 ment with fixed tones. Such a scheme must, however, 

 be made the basis of subsequent work. Moreover if com- 

 binations with what is called the harmonic Seventh or 

 6 : 7 be admitted, then we should require very nearly to 

 double the above number of separate notes. It follows, 

 therefore, that we must either restrict our desires of 

 modulation (which is not likely to happen) or be content 

 to use more or less imperfect intervals, and the question 

 turns upon the degree of endurable imperfection. It 

 must be remembered that these apparently innumerable 

 delicacies of sound present no real difficulty to the singer 

 or violinist when he once knows the theory on which they 

 have to be produced, for they are all generated by ex- 

 tremely simple intervals. The difficulty, indeed, is to 

 avoid them, especially in part music, and to put up with 

 alterations, apparently arbitrary and certainly neither 



1 " Sound and MuSic," by Dr. W. H. Stone, in the series of Science Lec- 

 tures at South Kensington, 1876, pp. 46. (Macmillan.) •n 



2 "An Elementary Treatise on Musical Intervals and Temperarnailt^ 

 with an Account ol the Enharmonic Harmonium Exhibited in the Loan Col- 

 lection of Scientific Instrnipients, South Kensington, 1876 ; also ot an Enhar- 

 monic Organ Exhibit^ftc the Musical Associat on of London, May, 1875," 

 pp. 94, 1876. (Maciranan.) 



3 For reasons and details see Helrahohz's " Sensations of Tone." 



4 See my translation of Helmholtz, pp. 669-672. 



