184 ANNUAL OF sci]:ntific discovery. 



searches into the subject of the dialysis of the electrical currents, 

 lately found that in passin<^ discharges from an induction coil, be- 

 tween the upper surface of a saline solution, contained in a glass 

 tube, and the extremity of a platinum wire fixed at a short distiuice, 

 the spark was surrounded with a cloud, colored according to the 

 sort of salt used in the experiment. 



Electricity of Steam. — In investigating the electricity of steam, 

 Faraday found that dry steam gave no excitement, and that the 

 electricity resulted from the friction of the vesicles of water 

 against the side« of the orifice. 



Collection of Electricity from the Air. — An English gentleman, 

 by means of a mile of insulated wire, sustained on poles 100 feet 

 high above the tall trees of his parlv, has collected, during a heavy 

 fog, enough free electricity from the atmosphere to charge and 

 discharge a battery of 50 jars and 73 square feet of coated surface, 

 20 times in a minute, with a report as loud as a cannon. 



Magnetic Disturbance during Volcanic Eruptions. — Professor Pal- 

 mieri, of Naples, who is engaged in making observations on all 

 phenomena connected with the last fire outbreak of Mt. Vesuvius, 

 states that he has never seen the magnetic needle so frequently 

 or seriously disturbed as it is at present, and the seismometer re- 

 cords at least 10 distinct earthquake shocks daily. 



Study of Longitude by Telegraph. — The actual difference of lon- 

 gitude between Washington and Havana, as demonstrated by 

 recent communication for the purpose, over the cable, is 5*^, 21' 

 and 8 2-10'^ The time occupied in the passage of electricity 

 between the two cities is thirty-five one-hundredths of a second. 



Tungsten Steel Magnets. — In a recent lecture, Mr. C. W. Sie- 

 mens spoke of the remarkable eftect of tungsten upon steel, in 

 increasing its power of retaining magnetism when hardened. A 

 horse-shoe magnet of ordinary steel, weighing 2 pounds, is con- 

 sidered of good quality when it bears 7 times it own weight. 

 The famous Haarlem magnet supports 13 times its own weight. 

 But Mr. Siemens has succeeded in producing a similar horse-shoe 

 magnet, of tungsten steel, which will carry 20 times its own weight, 

 suspended from its armature. 



Facts in Telegraphy. — In France, the greatest distance over 

 which a telegraphic message can be transmitted is about 600 

 miles; in Prussia, about 500; in Belgium, about 160; in Switzer- 

 land, about 200 miles. The charge for a message of 20 words, 

 over the greatest distance, in France, is Is. 8d. ; in Prussia, Is. 

 6d. ; in Belgium and in Switzerland, 5d. In Great Britain, 2s. is 

 charged for the transmission of a message over 500 or 600 miles, 

 and Is. 6d. for any message sent 160 or 200 miles. 



Expansion of Petroleum. — According to M. Deville (" Comptes 

 Rendus ") petroleum increases in bulk by one-hundredth of its 

 volume for every 10*^ C. of heat. A due allowance for this ex- 

 pansion is necessary in storing petroleum for fuel, or the casks 

 may be burst and destructive explosions ensue. 



Strength of the Wind. — In observatories generally anemome- 

 ters are made to register a force of 45 lbs. to the square foot, 36 

 lbs. being set down in the charts as a *' violent hurricane." In the 



