Sept. 1st, 18S7.] 



SCIENTIFIC NEWS. 



155 



wards with a kind of little hood at the lower part. These 

 curious forms of smoke are especially well seen when 

 beams of sunlight are admitted into the room across their 

 path. 



Fig. 5- 



Fig. 6. 



THE TINTOMETER. 



THIS instrument is used for the purpose of comparing 

 the depth of colour of a liquid or solid with a 

 standard scale of colour, so that the substance to be tested 

 may have its colour measured in degrees of a colour 

 scale. On referring to the accompanying illustrations, it 

 will be seen that Fig. 1 is a small perspective view of the 

 apparatus, and Fig. 2 an enlarged sectional view. The box 

 encloses two tubes, side by side, but not parallel, which are 

 separated by a partition F. Both the tubes arc open at AA, 

 and at C there is an eye-piece, which enables the operator 

 to see at the same time and under similar conditions the 

 standard colour D and the colour ED which is to be com- 

 pared with it. The standard of colour is formed by choosing 

 i\ glass slide faintly tinted with the colour to be standard- 

 ised, and if this be considered a single unit or degree of 

 colour, a scale is easily built up by adding successive units 



means of testing the degree of colour blindness, and of com- 

 paring the sight of two eyes. The maker is Mr. J. W. 

 Lovibond, of Salisbury, and the instrument can be seen in 

 the Chemical Section of the Manchester E.xhibition. 



THE TELEPHONE: ITS PRINCIPLES, 

 CONSTRUCTION, & APPLICATION.— II. 



IT has now been showp that the Bell telephone is com- 

 petent to act both as a receiving and transmitting 

 instrument, and that speech can be exchanged between 

 distant points without other apparatus. Practically, however, 

 the Bell instrument is not sufficient for commercial use. 

 The received sound is extremely feeble, and conversation 

 can only be carried on in a very quiet room. Quiet rooms 

 are out of the question in most offices and shops, and in 

 factories arc quite impossible. The feebleness of the Bell 

 instrument is due to the fact, that only a small fraction of 

 the total energy in the original sound-waves can be utilised 

 by the small diaphragm (and it is not found that larger 

 diaphragms improve matters), that there is more or less loss 

 in every transformation experienced by the original energy, 

 that energy is lost in the conducting circuit in the shape of 

 heating of the wires, and in the mechanical and magnetic 

 work done in both the transmitting and sending instru- 

 ments. The loss in the line is directly proportional to its 

 length, and is dependent on the size and material of the 

 conductor. An iron wire gives about six times as much 

 loss as a copper one of the same size, and a wire, one- 

 twentieth of an inch in diameter, four times as much as 

 one a tenth of an inch in diameter, other things being 

 equal. The working current being so small as to be hardly 

 measurable, stray currents from telegraph wires, electric 

 light circuits, or earth currents, interfere with speech, and 

 drown the weak voice of the receiving instrument; and this 

 suggests that, before leaving the Bell telephone, it ought 

 to be said that it is such a sensitive instrument to intermit- 

 tent, alternating, or vibratory currents, that it has been 

 largely used as a laboratory instrument in investigations 

 in which such currents are used, and that it has done ex- 



I, 



:|i||k T I.Ni TIilQ MC:T,E R 



Fig, I. The Tintometer, 



of the same colour. It is best to base the unit of colour on 

 a percentage solution of some known substance, so that it 

 can be checked or repeated at any time. The principle of 

 the instrument will doubtless be readily understood, and 

 its application, in the way described, to industrial purposes 

 is certainly ingenious, and bids fair to be very useful. 

 For instance, brewers can use it for ascertaining the 

 colour 01 pale malts before they buy them, and for find- 

 ing the colour value of highly dried malts. They can 

 also watch the increase or loss of colour during the pro- 

 cesses of manufacture. It is also suitable for deter- 

 mining the colour value of dyes, and for watching the loss 

 and change of colour under the influence of light. In the 

 analysis of water it is also useful as a means of finding the 

 degree of colour and turbiditj'. Many other applications 

 of this instrument might be mentioned, but those we have 

 referred to are sufficient to indicate its simplicity and use- 

 fulness. We may add, however, that it affords a ready 



Fig. 2. Enlarged Sectional View. 



cellent service in the hands of several scientists, chicr 

 among whom should be mentioned Professor Hughes, who 

 has used the telephone in his researches on magnetism with 

 most interesting and useful results. 



Now, it being proved in the first place, that an electric 

 current can be used to convey articulate sounds, and in the 

 second place, that the currents generated directly by such 

 sounds are too feeble for practical purposes, it soon sug- 

 gested itself to a number of people that the sound vibra- 

 tions might be used to control currents produced by batteries, 

 or other powerful sources of current. Just as a man, or 

 even a boy, can control the motion of a steam-engine, giving 

 out as much power as hundreds of men, and can direct that 

 power into various useful channels according to the require- 

 ments of his work, so it occurred to some people, that the 

 vibrating diaphragm of the transmitting telephone might be 

 made to control the flow of a much more powerful current 

 than it could possibly generate. This was, in fact, the first 



