Lecture on a new property of Magnetism. 525 



vigorous life and vigorous disease, as is observed in the 

 phlegmasia. In choleric seasons, attacks of gastric disorder 

 from excess, of colic, diarrhoea and dysentery, are often 

 observed to precede cholera at varying intervals. 



Tania. — Two cases have been treated, the worm passing 

 away in small joints only, attended by severe griping pain. 



Lecture on a new property of Magnetism, Delivered at the Royal 

 Institution. By Professor Faraday, D.C.L., F.R.S., $"c. 



Slow advance of science— form of a powerful electro-magnet — its power 

 illustrated by experiments — magnetic curves formed in the air — effect 

 upon an iron chain — magnetic bridge of iron — no attraction of lead and 

 some other metals — magnetised paper — new property of magnets — illus- 

 trated by bismuth — repulsion of this metal by the poles — magnets attract 

 some bodies, and repel others — phosphorous repelled by the magnetic 

 current — diamagnetism — all bodies attracted or repelled — the latter class 

 most numerous — lists of magnetic and diamagnetic bodies — diamagnetic 

 properties of water — substances, whether liquid, solid, or pulverulent, 

 point axially or equatorially — magnetic and diamagnetic properties of 

 air in different liquids — vegetable substances, if longitudinal, diamagnetic 

 — magnetism of the earth — phenomena of the dipping-needle — source of 

 magnetic attraction near the centre of the earth, not at the poles — relation 

 of diamagnetism to terrestrial magnetism. — Conclusion. 



Since the time that Lord Bacon taught us how to examine nature 

 by experiment, such an immense advance has been made in the 

 investigation of natural philosophy, that we are prepared at the 

 present day to expect a progress onward even from week to week, or 

 at all events from month to month, without any great surprise. But 

 when one considers the general system of nature, which changes 

 not ; that all its laws were established from the beginning, although 

 we may discover new facts, and perceive new relations of things, and 

 read laws of nature we call new, but which are as old as creation ; it 

 must occur to the mind as science advances more and more rapidly, 

 because of the light thrown upon it by our predecessors in philosophy, 

 and because of the increase in the number of students, still it in- 

 creases the difficulty to any one body, or one individual, or one nation 



