404 Miscellaneous Intelligence. 



shall not here detail the facts which have led me to general results, 

 because that would lead to too great length, and no advantage to 

 science would result from it, but I shall merely point out the fol- 

 lowing observations : — 



i. The wire made of iron from a sulphurous mine cannot be 

 magnetized ; it is the same with iron that has been highly tem- 

 pered ; to which, however, I have occasionally succeeded in com' 

 municating some slight degree of magnetism. 



ii. At low, or at least not high temperatures, such as — 6° R. 

 0°, and + 10°, only an equivocal magnetization is obtained; and it 

 is in vain to attempt to reverse the poles of a magnetized wire, 

 which I learned from a very long series of experiments made 

 during last winter. While by experimenting at a temperature of 

 + 20 b Cent, as Mrs. Somerville did, or at +25° or 26° R. as I 

 myself did during the June and the July of last year, very remark- 

 able results are obtained. 



iii. Rather thick wires acquire a perceptible magnetism, but with 

 difficulty. 



iv. By passing the violet ray from the middle to the extremity of 

 the needle, only weak and uncertain, if any, results are obtained. 



I shall finish this note by proposing to examine if the action of 

 the violet ray be not a chemical action. At first this action may 

 be attributed to the feeble currents which take place between the 

 red ray and the violet ray, and the existence of which I have several 

 times ascertained by means of a multiplier suitably arranged ; but 

 if such were the cause of the phenomenon, the part of the wire 

 placed under the violet ray ought, as it is evident, to acquire a 

 south pole : now it has been seen that it constantly acquires a north 

 pole. 



tt may also be thought that the magnetization in question is due 

 to the difference of temperature of the several parts of the wire ; 

 but then, again, according to the thermoelectric law, it is the south 

 pole which should be developed in the end exposed to the violet 

 ray. Beside, in this case, where the temperature is the same 

 throughout the whole extent of the wire, no magnetization should 

 take place ; now, we have seen (vi.), that a north pole is then formed 

 at each extremity. Lastly, I shall add, that having produced arti- 

 ficially a lower temperature than that of the surrounding atmos- 

 phere, I observed the same effects as before, although in a less 

 degree of intensity. These considerations lead me to think that 

 the violet ray acts chemically. I am confirmed in this opinion, by 

 seeing that the carburets and not the sulphurets of iron can acquire 

 magnetic properties ; that the needles artificially oxidized, present 

 the phenomenon in question more quickly and to a greater degree 

 than those which are not so ; and that, according to the degree of 

 temperature, the magnetic influence of the violet ray increases, 

 becomes weaker, and evanescent. To extend my views on this 



