108 ANNUAL OF SCIENTIFIC DISCOVERY. 



the gases introduced into the tube. As mixtures of certain gases, 

 such as carburetted hydrogen, carbonic acid, hydro-chloric acid, etc., 

 will produce a white light, nothing remained but to fill the tube with 

 such a mixture ; and this delicate operation was entrusted to M. Ruhm- 

 korff, who at the same time introduced other valuable improvements 

 into the apparatus. The latter has since been fairly tried in various 

 dental and other operations. 



Curious Electrical Phenomena. Mr. Gore, of Birmingham, who 

 has been for some time engaged making researches into the movements 

 of liquid metals and electrolytes in the voltaic circuit, has made the 

 following interesting discovery. If a large quantity of electricity be 

 made to pass through a suitable good conducting electrolyte into a 

 small surface of pure mercury, and especially if the mercurial surface 

 be in the form of a narrow strip about one-eighth of an inch wide, 

 strong vibrations occur, and symmetrical crispations of singular 

 beauty are produced, accompanied by definite sounds at the mutual 

 surfaces of the liquid metal and electrolyte. 



A new Electrometer has been invented by Mr. Thomas Sate, for 

 measuring the electrical charge of the prime conductor of a machine, 

 and is described by him in the Phil. Magazine. It is termed the si- 

 phon electrometer ; and stated to be sufficiently delicate and reliable 

 in its indications ; and to admit of being constructed so that the results 

 derived from one instrument may be fairly compared with those de- 

 rived from another instrument. It depends on the principle that 

 different quantities of electricity discharge different quantities of 

 liquid from a siphon-tube in which the liquid is suspended by capillary 

 action. A glass jar, containing water, about four inches in diameter, 

 is placed upon an insulating stand of gutta-percha ; a small siphon 

 about .15 of an inch diameter is cemented to the side of the jar. A 

 funnel-shaped receiver, about three inches in diameter, is connected 

 with the ground by a damp cord, and placed directly below the ori- 

 fice of the tube, and connected with a glass tube divided into tenths 

 and hundredths of a cubic inch, and a conducting wire is fixed to 

 the prime conductor of the electrical machine and drops into the 

 liquid. The instrument is used in the following manner : a sufficient 

 quantity of water is poured into the jar, so as to cause the siphon to 

 act ; the water then flows through the siphon until its pressure in the 

 jar is balanced by the capillary action of the tube, when it will cease 

 to flow. It will then be found that the level of the water in the jar 

 stands somewhat above the orifice of the siphon-tube. Scarcely any 

 amount of shaking or oscillation will now cause the water to flow 

 from the orifice. The graduated tube is then placed below the ori- 

 fice, the bottom of the funnel being from two and one-quarter to two 

 and one-half inches from this orifice. The machine is then turned, 

 and the electric action causes water to flow in a continuous stream 

 or jet from the orifice, filling the tube. Any proposed number of 

 revolutions being given to the machine in a known time, the number 

 of cubic inches of water discharged is taken as the measure of the 

 efficiency of the machine. 



The Duration of the Electric Spark. The duration of the elec- 

 tric spark which accompanies the discharge of a conductor is the 

 subject of a note by Professor P. Rijhe, of Ley den, in the Biblio- 



