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ch, and gave a single reversible sound. "Ho," when turned back, sounded distinctly "och."

Since both vowels and consonants sound alike backwards and forwards, it appears that articulate speech may be divided into a series of successive parts, each having a character of its own, and each reversible so far as sensation is concerned.

The separate reversible sensations correspond in the main to the letters of our alphabet, but our letter i represents at least two reversible elements, and ch, ng, or th, on the contrary, are single sounds. Clear, clean sounds, as spoken by educated people in all countries, seem remarkable for the small number of the elements that enter into each word. An uneducated man, speaking a dialect or patois, will make each nominal vowel consist of a large group of simple reversible sounds running into one another.

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6. The wave form for the letter r has been recorded. with that obtained by Donders on the phonautograph, and consists of a series of simple curves, similar to harmonic curves, which gradually increase to a maximum, and then gradually decrease to a minimum. The number of waves separating the maximum from the minimum intensity of the sound was in the examples observed 7 or 8. The length of the whole period was therefore 14 or 16.

7. The wave forms obtained from the letter o in figs. 4 and 5 illustrate the difficulty which the ear, even of trained musicians, feels in determining the octave in which a given note is sung. It will be seen that each period consists of two very nearly equal parts, and that the amplitude of the second partial has obviously been large as compared with that of the prime tone. To one ear it might seem natural to call the pitch that of the second partial, since this was the loudest tone; to another the pitch would be that of the prime, because this tone was lowest in pitch. Naming a given note by the lowest of its component tones, irrespective of the relative intensity of the partials, seems to be a convenient but conventional rule.

8. The instrument as at present made does not record all sounds. This is shown by the fact that its reproduction of the French u is very imperfect, and ee is only sometimes well heard from it.

The curves laid before the Society were obtained by multiplying the traces on the tinfoil some 300 times by means of a system of

levers. The lines were drawn on the paper by the plan of frictionless marking invented by Sir William Thomson, and used in his Siphon Recorder. A rise in the curve (on the page) corresponds to a hollow in the tinfoil. The arrow pointing from right to left, indicates the direction in which the tinfoil passed under the vibrating pointer when the sounds were uttered.

The authors hope soon to be able to communicate to the Society the results obtained by subjecting the experimentally drawn wave forms to harmonic analysis.

Fig. 1 gives the curve made by the sound of oo, as in "food," on

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the note b; fig. 2 is oo on f by the same voice; and fig. 3 is a still

Fig. 2.

Fig. 3.

higher oo by another voice. As the speed at which the phonograph was turned was very nearly the same in all the examples, the relative

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pitches are approximately given by the lengths of the periods.

Figs. 4, 5, and 6 show the waves given by the sound "oh," spoken at

Fig. 5.

Fig. 6.

various pitches by the same voice (that of Dr Crum Brown). Figs.

Fig. 7.

Fig. 8.

7 and 8 are given by the sound a in "father," the first on e by Sir R. Christison, the second on c' by Professor Jenkin.

3. On the Action of the Chlorides of Iodine upon Acetylene and Ethylene. By George M'Gowan.

Before giving the action of ethylene on the chlorides of iodine, I may shortly describe the method of preparing the latter, which I found to be the most advantageous :—

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A weighed quantity of perfectly dry iodine being introduced into

bulb A of flask 1, perfectly dry chlorine gas is passed over it, A being at the same time heated over a water-bath to about 60° to 80° C. The ICl, as it is formed, volatilises and condenses almost entirely in B, only a small portion escaping into flask 2. Chlorine is passed until no more iodine remains in bulb A. If the heating be omitted, only the outermost layers of iodine are converted into the trichloride, a kernel remaining unacted on. (Compare Christomanos, Berl. Ber. X. No. 5, p. 434.)

The tubes connecting the two flasks are ground into one another at D, so that no cork or caoutchouc fittings are required. This is absolutely necessary.

By attaching a small CaCl, tube to E, no moisture can enter the apparatus. The flasks can be weighed either together or separately. When passing ethylene or acetylene over either of the iodine chlorides, I found it best to cleanse and dry flask 2, leaving the gas to act on the chloride in 1. In that way any volatilised matter from 1 was condensed in 2, and the loss of weight was very trifling.

By adding the required weight of iodine to the IC, and heating gently over a water-bath (the vessel being corked), ICl is easily prepared. I invariably got it in the state of long needles.*

Action of Ethylene (С2H) on IC1 ̧.

By passing pure dry C2H over pure dry ICl, at 0° C., the two compounds chloride and chloriodide of ethylene are formed. This reaction takes place quantitatively, thus:

(C2H1)2 + IC12 = С2H1Cl2+C2H ̧C1I.

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It is generally stated that ICl dissolves in alcohol and ether, forming yellow solution. (See Watts's Dict. of Chem. vol. iii. p. 293, new ed.) The fact is, that if ether (perfectly free from water and alcohol) be dropped into ICl, a most violent reaction ensues. If, on the other hand, ICl be dropped into a large excess of ether (or alcohol) at 0°, it dissolves, at first forming a pale yellow-brown solution; but, in the course of a few minutes, the ether becomes darker and darker from separation of iodine. The chlorine probably acts on the ether to form dichlor-ether (CH,Cl2O) for the most part. This requires to be investigated. 4 I

VOL. IX.

After saturation, the fluid was almost colourless, having only a pink tinge of iodine. The two above fluids can (after washing with dilute KOH and drying) with some difficulty be fractionated. C2H4Cl boils at 85° (Fittig).

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Having prepared about a kilo. of C,H,Br2, I decomposed it according to the method described by Sabanjeff (Annalen, Band 178). Briefly described, this method is as follows:-Into a thick flask of

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about one litre capacity, more than half filled with a concentrated alcoholic solution of KOH, and heated over a water-bath to 100° or thereabouts, CH4Bг2, pure or diluted with alcohol, is slowly and regularly dropped from a separating funnel. The CH, disengaged, passes off through an upright Liebig's condenser, also affixed to the flask, by which means most of the monobrom-ethylene (C,H,Br) formed at first, and carried away along with the CH2, is returned to the flask. Some of it, however, escapes undecomposed from this flask into a second one, also containing alcoholic KOH, and fitted with

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