NATURAL PHILOSOPHY. ] 19 



This country affords much better opportunities than Great Britain 

 for observing the phenomena connected with thunderstorms, on ac- 

 count of their greater frequency and severity, and it is therefore to be 

 desired that some of our scientific men should commence a series of 

 observations with a view of ascertaining whether rain is really the 

 cause of lightning. 



CONNECTION OF THE AURORA BOREALIS WITH ELECTRICITY. 



THE connection of the aurora borealis with electricity, a fact 

 which has been taken for granted since the days of Franklin, has only 

 lately been fully established. Mr. E. C. Herrick, of New Haven, has 

 recently observed an electrical action on the wires of the telegraph 

 at that place during the occurrence of an aurora. The same fact 

 has been also noticed in England and on the Continent during the last 

 year. During the aurora of the 17th of November, 1848, the tele- 

 graph at Watford, England, was violently affected for many hours. On 

 several occasions the electric current passing was sufficiently powerful 

 to attract the movable armature of the stationary electro-magnet of 

 a bell apparatus, so as to allow the alarm to be sounded. To effect 

 this, the pressure of one third of an ounce was found by experiment 

 to be necessary, and from a calculation based on the length and thick- 

 ness of the wires, it is supposed that the power of an aurora, if sim- 

 ilarly extended over a square mile of surface, would be equivalent to 

 the lifting of seventy-five tons. It has not been fully ascertained, 

 whether the action is one of actual transfer of electricity from the 

 space at one end of the wire to that at the other, whether it is an 

 inductive action of the aurora at a distance, disturbing for an instant 

 the electrical equilibrium of the wire. 



A NEW MODE OF DISCHARGING A LEYDEN BATTERY. 



WE find in the London Mechanic's Magazine a notice of a novel 

 method of discharging a Leyden battery, which has lately been ex- 

 hibited before the Polytechnic Institution. In this new method the 

 jars are . arranged in a series, with the knob of each in connection 

 with the outer coating of the next in the series, as has often been 

 done heretofore in the process of charging them. In our case, how- 

 ever, they are charged separately, or are first connected together in 

 a battery in the ordinary way. When ready to be discharged, they 

 are by a simple movement all insulated and arranged in a series as 

 described above, which may be made to take a semicircular or U form, 

 in order to bring the knob of the last jar in the series into convenient 

 proximity to the outer coating of the first jar. The effect of this ar- 

 rangement is to multiply the intensity in a manner analogous to that 

 of the galvanic battery, so that if the outer coating of the first jar be 

 supposed to be in connection with the earth, and the number of jars 

 be twelve, the knob of the last jar will be twelve times more highly 

 electrified than the knob of either jar was before being thrown into 

 the series. The disruptive or space-penetrating force is consequently 



