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Account of a rotatory Gas-Burner . 
full ; and B is a tube which rises from the bottom, and through 
the centre of the water-case, and which is perforated with holes 
above the top of the water-case. In the top of the tube B is a steel 
centre, terminating with a fine point, upon which the inverted 
tube C revolves. This inverted tube C seals itself in the water, 
and does not allow the gas emitted from the holes of the tube B 
to escape ; and it has four arms of equal length, and finely bored 
with small holes at the extremity of each arm for the gas to 
burn at. All these holes are and must be at the same side of 
each arm, to give the burner motion ; some of the holes are put 
in a vertical direction, and some inclined at angles to those holes 
in the sides. This part of the burner is susceptible of great 
variety of contrivances, and may be carried into multiform 
shapes and figures, which, added to the perpetual revolving mo- 
tion of the ^hole, gives a beautiful brilliancy, very pleasing to 
the eye. 
The theory of it is extremely simple, and is only, that the 
rotatory motion is produced by the pressure of the gas from the 
gasometer being so diminished on one side of the arms of the 
burner, by the small emission gas-holes, as to cause an increase 
of pressure on the other side of the tube, and thus to make the 
whole revolve by the smallest pressure the gas can burn at. 
The water-joint is necessary to prevent the escape of the gas, 
and to allow the burner to have an easy motion on the steel 
point. The revolving burner is very plain and simple in its 
action ; but I am convinced, from the many attempts that have 
been unsuccessfully made by others to discover such a contri- 
vance, that, were it publicly known, it would be of great use 
and convenience for many of the purposes of life. 
Art. XVI.- — Notice regarding the Phosphate of Lime of the 
Coal Formation. By M. P. Berthier. 
Toward the end of the last year, Messrs Manby and 
Wilson sent to the laboratory of the School of Mines, for exami- 
nation, specimens of the different ores of iron which the Riant 
Company propose to work. Among those specimens there was 
one which contained but very little iron, and which I presently 
