Feb. 25, 1875J 



NATURE 



325 



volume abounds. Neither is the work free from the 

 grave charge of inaccuracy. The writer who speaks of 

 the sun as an " everlasting, universal, equable heat 

 source," cannot be acquainted with Sir Wm. Thomson's 

 paper on the dissipation of energy. On page 37 the 

 equivalent of iodine is stated to be 125 ; on page 46 we 

 are told that potassium is negative to sulphur. It will be 

 new to our readers to learn (p. 50) that " attraction in 

 chemistry does not differ from that in physics," and that 

 carbon disulphide is prepared (p. 52) by powdering, 

 mixing, and heating carbon with sulphur. On page 108 

 we are informed that " latent heat is, by the study of 

 galvanism, resolvable into electricity." We do not differ 

 from Dr. Hall in considering the following idea of the 

 cause of electro-magnetism as " most rudimentary and 

 rough." Speaking of a solenoid, the author states (p. 116), 

 " Such a solenoid or its latent-heat current will avoid the 

 latently hot pnrts of the earth — that is, her equator — and 

 will place itself at right angles to the equator — that is, 

 move away fiom the equator as far as it can ; will, in fact, 

 assume a position parallel to the magnetic meridian of 

 the place, &c." The phraseology adopted by Dr. Hall 

 must be characterised as eminently original ; we select a 

 few expressions to submit to the judgment of our readers : 

 — " Proto-metalloidations," " nitridations," " hydro-solu- 

 ble," ''tensified, unmorphigenic electroid," " disoccupied," 

 "very unnegative hydrogen," '■ hydrohalogenic acid," 

 " equo-terro-solar equilibrium," " protometalloidid," " dis- 

 equilibrium." The description of the combustion of 

 carbon is perhaps worth quoting entire : — " Carbon com- 

 bines with oxygen, leaves its solid shape for a gaseous 

 one, forming carbonic anhydrid gas, and this greatly 

 because of carbon's own heat constitution ; and, further, 

 because of the intense nearness of the oxygen to carbon 

 and our earth's comparative distance ; this because also 

 of the excellent heat capacity of oxygen itself : and thus 

 carbon with oxygen leaps up into carbonic anhydrid gas, 

 earth loosened into the highest sun forms, approaching 

 that of oxygen itself, for the heat capacities of carbon are 

 near those of oxygen : but the oxy-terric struggle for car- 

 bon is arduous ; our earth has greatly in her favour her 

 immensity, but then she is far off, and her forces decrease 

 with distance ; but even so, for freeing carbon from our 

 earth's control, oxygen requires always, as we know, the 

 further assistance of heat on carbon ; we always, for oxy- 

 carbonic combination, have to set fire to carbon." On 

 p. 34 we are gravely informed that potassium, even under 

 naphtha, is acted upon by sun and earth forces, and 

 becomes covered with an " allotropic crust." The author 

 then gofs on to remark that this behaviour arises from 

 the fact that free potassium is " not a child of nature or 

 of our sun, but of furnace heat, and its equilibrium taken 

 with furnace heat must become slowly changed to that of 

 our sun." In the new theory a metallic protoxide is thus 

 foimularised : E^M^O, "in which E stands for our 

 negative earth, and x lor the part she takes in the action 

 not quantitatively known" — we may venture to add, nor 

 yet qualitatively. It would be as tedious as unnecessary 

 to give further quotations in illustration of the manner in 

 which Dr. Hall has handled his subject — the extracts 

 given above will doubtless seiTe as a caution to readers 

 intending to take up the book. The selections themselves 

 will render further comment a work of supererogation. 



LETTERS TO THE EDITOR 



\The Editor does not hold himself res fonsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond with the writers cf rejected manuscripts. 

 A'o notice is taken op anonymous communications.^ 



On the Building up of the Tone in the " Gamba " Organ- 

 pipe 

 In considering the nature of this pipe, and in determining the 

 relation of its air-reed and its air-column, one fact discovered in 



these investigations should always be borne in mind, that the 

 pitch of the reed is dependent not on vibrating length but on 

 vibrating divergence— on the amplitude of the reed's 'motion 

 The pitch of the air-column is not necessarily the same as the 

 pitch of the air-rced ; they may be and often are at variance : 

 and this pipe will afford a happy means of demonstration of the 

 statement made in a previous letter, that the tone of every organ- 

 pipe is dual. As regards the reed, whatever the modifications 

 of length by height of mouth, of thickness by varied wind-way, 

 or of strength by amount of wind-pressure, the final result is 

 bound by this law of divergence. In the typical air-reed, any 

 deviation from the direct line of force taken by the stream of air 

 is the beginning of vibration ; its highest possible rate of vibra- 

 tion begins existence on its least divergence from the direct line ; 

 consequently, its highest pitch is its inceptive tone at this staf e 

 or condition of uiitamed energy. The bass lias always been 

 considered the basis and commencement of musical tone ; every 

 relation of tones has been examined on that ground, and it has 

 undoubtedly been the source of many errors, one might almost 

 say in the nature of superstitions, so tenacious has been its hold, 

 so blinding its influence on the perceptions. Tone has its 

 beginnings in the higliest activity, and descends to the lowest 

 and slowest ; the development of its mechanical relations pro- 

 ceeds by definite degrees, and the issue depends on the affinity 

 existing between the pipe and the reed, both possessing definite 

 form, power, and character, and blending these by law. The 

 vibration of the aeroplastic reed is thus shown to he isotonic, net 

 iiochronous ; the laws of its vibrations are identical with those of 

 the things most like itself, of sound-waves, of light-waves. 



It was my good fortune some time ago to have placed in my 

 hands a specimen of a variety of "Gamba" devised by the 

 famous organ-builder, Schulze, of Paulenzelle. The "Gambas ' 

 form a class of pipes variously constructed in scale, and they are 

 so called from the quality of their tone imitating the old " Viol 

 da Gamba " and its modern representative the "violoncello." 

 The general characteristics of the class are— cylindrical pipe of 

 comparatively slender scale, low-cut mouth, full-winded at foot, 

 and slow in speaking ; the slow speech is a necessity, and is 

 caused by the wind being, as it is technically termed, "much 

 thrown out ;" that is, the line of force of the current of wind is 

 set more outward than ordinarily, for without such arrann-ement 

 tlie fundamental or ground tone of the pipe would not secure its 

 hold ; some harmonic would usurp possession ; for the air-reed, 

 being short in consequence of low mouth, and strong from excess 

 of wind, would keep to harmonics as the "flute harraonique " 

 does ; the latter has a low languid (or interior level within the 

 mouth), the "Gamba" has a higher languid in relation to the 

 under lip, thus directing the stream at a more oblique angle to 

 that level. The tone has decided introductory and transitive 

 liarmonics. Of their sequence, ahliough but momentary, the 

 ear conveys a clear impression to our consciousness. We call it 

 a "stringy quahty," and it is a very mteresting inquiry how this 

 peculiar pipe-tone is built up. The characteristic quality per- 

 taining to all stringed instruments whose tone is elicited by the 

 bow, does, we may well suppose, arise through a process bearing 

 a close analogy to this. 



It is a disadvantage, this slow speech of the " Gamba," often 

 felt to be excessively slow. Most skilful voicing is needful to give 

 sufficient time for the appearance of the introductory harmonics 

 without too greatly delaying the fundamental, for it is a nice 

 point to strike the mean between having the wind so much 

 llirown out that the pipe wUl not speak any tone, and risking, by 

 giving quicker speech, the sudden "flying off to the octave," 

 with obstinate persistence not to descend. 



Take note of this. If you hold your hand or your finger near 

 the mouth cf any speaking organ-pipe, there is forthwith a 

 sensible flattening of its pitch, deepening with the nearer ap- 

 proach of the hand ; in tuning organs it is the ordinary custom 

 to test pitch by this simple method, determining thereby whether 

 the pipe will best bear flattening for its nearer approximation to 

 a desired pitch or concord with others. Suppose yourself to be 

 tuning a set of " Gamba " pipes : you would notice perchance that 

 a restive pipe eontinuallv darting off to harmonics would be 

 corrected and steadily held in check so long as your hand or 

 finger was near or across its mouth. We can thus well under- 

 stand how it might occur to Schulze that the temporary ex- 

 pedient could be made permanent. This is what Scliuize did : 

 he fixed a small bar across the mouth. The device proved 

 successful. In pipes thus treated the tendency of the reed to 

 settle at the octave is suppressed, speech is quickened, more wind 

 may be given without clanger, ami the quality becomes in con- 



