170 Intelligence and Miscellaneous Articles. 



position of a judge to assume the character of a partisan and advo- 

 cate, and when I also see it conferring a distinction, which, to be 

 appreciated, ought only to be the reward of undoubted merit, on one 

 who clearly does not ])ossess that merit, I feel that it would ill be- 

 come me to retain such a distinction any longer." 



SINGULAR PROPERTY, AND EXTRAORDINARY SIZE AND LENGTH 

 OF THE SECONDARY SPARK. BY PROF. CHAS. G. PAGE, M.D. 



In experimenting with my great magnet, a new property of the 

 secondary spark has been discovered and some very interesting facts 

 elicited. 1 will premise that the helix, nearly a foot in diameter 

 each way, when charged by the battery, draws up within it in a 

 vertical position a huge bar of iron weighing 300 pounds through a 

 distance of ten inches, presenting by far the most powerful magnet 

 ever kno\\'n. When the circuit with the helix is suddenly broken, 

 a secondary spark is produced eight inches in length. 



The most interesting feature of this spark is the modification of 

 its form and sound by the action of magnetism. When the spark is 

 produced at a distance from the magnet, it is readily elongated to 

 six or eight inches, and I presume might be obtained a foot or more 

 in length if the wires were separated with the velocity of a cannon- 

 ball, as suggested by my friend Mr. Lane. In this case there is 

 little or no noise made by the spark ; but as the spark is produced 

 nearer to the magnetic pole, the sound increases, until at last, when 

 close to the pole, each spark makes a report as loud as a pistol. 

 The spark also diminishes in length, and is spread out as large as 

 the pjilm of the hand. There is an effect here somewhat analogous 

 to that produced by a magnet upon the arc of flame between charcoal 

 points. — From Silliman's American Journal for November 1850. 



ON THE EQUIVALENT OF MAGNESIUM. 

 BY MM. R. F. MARCHAND AND TH. SCHEERER. 



The uncertainty which still exists as to the true chemical equiva- 

 lent of magnesium, notwithstanding the numerous experiments on 

 the subject, induced the authors to undertake fresh researches to 

 settle the question. 



The process which these chemists adopted to determine this sub- 

 ject, consists in ascertaining the quantity of carbonic acid contained 

 in a given quantity of native carbonate of magnesia. 'Ilie mineral 

 which principall}'^ served for these experiments is the magnesite of 

 Frankenstein, of which very pure specimens were obtained. The 

 numerous experiments which the authors performed show that the 

 choice of the mineral is in nowise indifferent. When magnesite 

 contains considerable quantities of silica, carbonate of iron, alumina, 

 and especially water, which it is almost impossible to expel by drying 

 without simultaneously disengaging small quantities of carbonic acid, 

 it is unfit for the purpose of analysis. 



The magnesite of Frankenstein contains only 0'05 per cent, of 

 foreign matter, of which an account is taken in the calculations. A 

 certain quantity of this mineral, well-powdered, was introduced into a 



