246 Miscellaneous Communications. 



discern the gas flowing down the hollows leading from this to the 

 lake. When I had satisfied myself with' these experiments, the cus- 

 tode took both the torches, and rubbing them against the sides of the 

 cave, filled the bottom of it with smoke ; the hitherto invisible spirit 

 of the cave took form and substance j and I was warned by a gentle 

 hint, for half a dollar, that the exhibition was at an end. 



Art. III. — Miscellaneous Communications, from Dr. Hare. 



There is scarcely any one of the phenomena produced by a pow- 

 erful voltaic series, which creates greater surprise in the beholders, 

 than the intense ignition which ensues, when a platina wire of about 

 No. 24, connected with the negative pole, is brought into contact 

 with the surface of a concentrated solution of muriate of lime. The 

 end of the wire quickly fuses and falls to the bottom of the glass in 

 successive drops, which are so perfectly globular as to indicate that a 

 high degree of fluidity must have preceded their congelation. The 

 communication of the liquid with the positive pole, which is of 

 course indispensable to this experiment, is effected by the employ- 

 ment of a platina wire much stouter than that which is above descri- 

 bed in connexion with the negative pole. This brings me to the 

 most inexplicable feature in the case, which is, that if the arrange- 

 ment be reversed, so that with the smaller wire in communication 

 with the positive pole, and in contact with the surface of the liquid, 

 the series be brought into action, the ignition is comparatively feeble, 

 and will not effect the fusion of the wire. 



I have a magnet made essentially after the plan of Prof. Henry, 

 excepting the use of paper and shell lac, in lieu of silk as an insula- 

 tor, which method I devised and mentioned to you more than two 

 years ago. 



This magnet weighs seventeen pounds. It is surrounded by four- 

 teen coils of copper wire. No. 15, each sixty feet in length. Its 

 maximum of cohesive power is equal to seven hundred and eighty 

 pounds. 



I was curious to see if there would be any re-action between this 

 magnet and the jet of igneous matter between the poles of a de- 

 flagrator, of seven hundred pairs of plates of four inches by three. 

 The only remarkable result was, that the conducting power of the 

 iron of the magnet was much reduced when subject to the induc- 

 tive influence of the coils. 





