218 
POPULAR SCIENCE REVIEW. 
conductors on tlie fine old Hotel de Ville at Brussels. Instead of single 
rods lie employs bundles or groups of points, branching out in all directions, 
connected with numerous ramified conductors meeting in a solid block of 
galvanized iron, from which three series of ramified wires sunk like roots in 
the ground are connected, one communicating with a well under the court, 
the two others passing through iron pipes full of gas tar, until they reach the 
gas and water mains of the town. 
Toughened Glass . — An improved method of producing annealed or tough- 
ened glass has been adopted by M. de Labastie. He throws the soft arti- 
cles, immediately on their being blown, at once into the annealing bath, so 
as to save a second heating, and the consequent danger of loss of shape. 
Automatic Gas Lighting . — An ingenious plan for accomplishing this 
object has been brought before the Society of Arts by Mr. Fox. Each lamp 
is supplied with a small induction coil, the primary wires of all being united, 
and the secondary with condensers composed of glass plates and tin foil laid 
alternately side by side. The soft iron core of the induction coil is also used 
to produce reciprocating horizontal motion in a permanent horseshoe magnet 
suspended on needle-points just above the coil. A stop-cock is actuated by 
the reciprocating magnet, and thus the gas can be turned on immediately 
before the lighting spark passes. The whole apparatus is contained in an 
air-tight metallic case, measuring 2J inches high by 2\ inches wide, screwed 
on to the supply pipe of the lamp, the insulated wire being either carried 
underground, or as in some experiments now in progress in Waterloo Place 
and Pall Mall, hung from small telegraph poles attached to the tops of the 
lamp standards. 
The Compass of Ancient Flutes. — M. V. Mahillon has been able to 
reproduce successfully the tone and scale of the ancient flutes found at 
Pompeii. 
A similar determination was made in 1876 by Mr. W. Chappell and Dr. 
Stone for facsimile copies of the Egyptian flutes preserved in the British 
Museum, and in that of Turin. These were exhibited and played on during 
the Loan Exhibition of Scientific Instruments at South Kensington. The 
reed then used was that which can be made from a simple joint of long 
grass by means of a longitudinal flap cut upwards towards the closed node. 
This, the most ancient form of reed, as described in u Tyndall on Sound,” is 
often made by children in the fields, and called a “ Squeaker,” and still 
exists in the drones of the ordinary bagpipe. 
M. Mahillon made use of a similar single beating reed, to be found in the 
Ar ghoul, or Egyptian flute. Taking for granted what is rather matter of 
doubt, namely that the chromatic scale was known to the ancients, M. 
Mahillon concluded that if the thirteenth sound obtained was the octave of 
the first, the intermediate notes must be correct. Thus B, on the second 
line of the Bass clef is obtained as the fundamental or lowest note of the 
instrument, and the following notes are successively obtained by opening 
the lateral notes, C sharp, D, E, F, F sharp, G, G sharp, G sharp, A, 
B flat, B natural. The absence of 0 and of D sharp is accounted for by the 
fact that the second and fifth rings of the instrument are not bored. It is 
possible this may be due to the fact that they would, if open, exceed the 
number of the digits, though M. Mahillon does not advert to this point. The 
