128 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



electric light in increasing the "brightness of the arc. The 

 substances used were bone-ash, calcium chloride, borate and 

 silicate, silica, magnesia, magnesium borate and phosphate, 

 alumina, and aluminum silicate. The proportions were so 

 regulated that, when burned, the carbons should contain 

 about five per cent, of the foreign substance. The results 

 show that only with the bone-ash was the light increased 

 measurably, but that the fumes produced are serious objec- 

 tions to the use even of this. 



Reynier has suggested a new form of electric lamp, the 

 carbons in which have the form of disks, in contact, or near- 

 ly so, at their peripheries, and rotated by clock-work. To 

 one of them an automatic arrangement is attached, which 

 electro-magnetically controls the distance between the elec- 

 trodes, and that instantaneously. This device, the author be- 

 lieves, will enable him to divide the current, and so to main- 

 tain several electric lights at the same time by a single 

 machine. 



Chikolef has made a series of experiments at St. Peters- 

 burg to determine the lighting power of the electric light at 

 great distances. The power of the light is notably increased 

 by covering the carbon of the lamp with a thin sheet of cop- 

 per (one sixteenth of the diameter of the carbon at its upper 

 part, and from one forty-eighth to one sixty-fourth in its 

 lower part). It depends also upon the direction given to 

 the carbon, the best being to turn the cup towards the ob- 

 ject to be lighted. The great machine of Alteneck, with a 

 carbon twelve millimeters in diameter, gave a maximum 

 light equal to 10,210 candles, and a mean light of 5739 can- 

 dles; while with a carbon of ten millimeters, but galvanic- 

 ally coated, it gave a maximum of 10,255 candles (20,275 

 when the cup is turned as above), and a mean of 14,039 can- 

 dles. The light was sufficient to make objects visible (for 

 military purposes) at a distance of 3080 yards. Of many 

 machines used, the most economical proved to be the great 

 Alteneck. 



Jablochkoff has devised a new form of electric lamp, very 

 simple in its construction, having absolutely none of the me- 

 chanical arrangements ordinarily used. It consists of two 

 carbons permanently fastened parallel to each other, and at 

 a small distance apart, separated by some insulating sub- 



