E'conomical illumination by Electric Light. 385 
of the vase. This fact is proved anew by the researches just 
published of M. Gaugain, although the a obtained differ in 
the details from those of the German physicist 
Economical illumination by Electric light. ~The last winter, 
the General Dock Company, hurried in the founding of its estab- 
lishment, was obliged to work night and day. It ‘undertook to 
remove in a short time the whole of a considerable hill: 1600 
workmen, 800 at a time, were kept at work without interruption. 
In order to illuminate the works during the hours of the night, 
they proposed to use electric light. This mode of illumination 
as been often used in Paris in works at night; but in this case 
it was continued for 4 months, and proved to be an economical 
method of lighting. Fifty of Bunsen’s elements were at once in 
action, and when the light after a while diminished, another 50 
were substituted. Two electric lanterns served to light the space 
where the 800 workmen were employed. The expense per lan- 
tern was as follows: 
elite eae! ys day, . : ; . 4-50 franes. 
Mercur ; j ‘ 5:00 
inc : . ‘ : 4:50 
Points of charcoal, : : ‘ : 1-40 
Nitric acid, ; - ; ‘ Mig! 5: 
Sulphuric acid, ; ; : : ; 1:84 
Total <. : ; ; 19-04 
The cost, hence, of lighting the 800 workmen, was 38 francs 
8 centimes per night, or 43 centimes per man. This isa very 
considerable economy, and the work went on with a regularity 
Which _ would have been impossible with any other mode of 
ger, although the place was incessantly traversed by locomotives 
engaged in transporting the earth. 
Decomposition of Kyanite by galvanic heat.—Another use has 
been made of electricity, and this of a chemical nature. 
attaching to one of the charcoal points of a Bunsen’s battery of 
80 elements a small lamellar fragment of kyanite, which, as is 
well known, is very infusible, M. Duvivier has succeeded in fus- © 
ing it in 3 or 4 minutes; the ‘elements of which it consists were 
in part dispersed, and the aluminium, freed aye oxygen, ‘aloe be 
: xs surface of the substance in fusion. 
e fixed to the surface of the assay, isch ean tened 0 
ole and other globules remained imbedded i in the filed 
mass. The author has extracted some of the supposed alumin- 
ium, but has not examined its physical properties, and we cannot 
Say that it was pure; it may have contained silicium, proceeding 
sath ee silica. Has this deoxydation been age by the heat 
ND Serres, Vol. a No. 54.—Noy., 1854, 
