406 Description of a ?iew Mercurial Trough. 



because, as will be seen hereafter, iron is always and in almost 

 all states magnetic. But in respect to this point it may be 

 observed, that the ordinary magnetic property of matter and 

 this new property are in their effects opposed to each other ; 

 and that when this property is strong it may overcome a very 

 slight degree of ordinary magnetic force, just as also a certain 

 amount of the magnetic property may oppose and effectually 

 hide the presence of this force (2422.). It is this circumstance 

 which makes it so necessary to be careful in examining the 

 magnetic condition of the bodies in the first instance (2250.). 

 The following list of a few substances, which were found 

 slightly magnetic, will illustrate this point: — Paper, sealing- 

 wax, china ink, Berlin porcelain, silkworm-gut, asbestos, fluor- 

 spar, red lead, vermilion, peroxide of lead, sulphate of zinc, 

 tourmaline, plumbago, shell-lac, charcoal. In some of these 

 cases the magnetism was generally diffused through the body, 

 in other cases it was limited to a particular part. 



2286. Having arrived at this point, I may observe, that we 

 can now have no difficulty in admitting that the phenomena 

 abundantly establish the existence of a magnetic property in 

 matter new to our knowledge. Not the least interesting of 

 the consequences that flow from it, is the manner in which it 

 disposes of the assertion which has sometimes been made, that 

 all bodies are magnetic. Those who hold this view, mean 

 that all bodies are magnetic as iron is, and say that they point 

 between the poles. The new facts give not a mere negative 

 to this statement, but something beyond, namely, an affirma- 

 tive as to the existence of forces in all ordinary bodies, directly 

 the opposite of those existing in magnetic bodies, for whereas 

 those practically produce attraction, these produce repulsion ; 

 those set a body in the axial direction, but these make it take 

 up an equatorial position : and the facts with regard to bodies 

 generally are exactly the reverse of those which the view 

 quoted indicates. 



[To be continued.] 



LXVII. Description of a new Mercurial Trough. 

 By Professor Lou yet of Brussels*. 



TN small laboratories in which one of the chief points to 

 ■*• be aimed at is ceconomy, in making researches on gases 

 soluble in water, a small porcelain trough is commonly em- 

 ployed capable of containing twenty to twenty-five pounds of 

 mercury. The size of the bell-glass is proportioned to the capa- 

 city of the trough ; thus only small quantities of gas can be 

 * Communicated through Prof. Grove, by the Author. 



