GAL VANISM MAGNE TISM. 



99 



stances, have been inflamed charcoal has been 

 made to burn with a most brilliant and beautiful 

 white flame water has been decomposed into 

 its elementary parts metals have been melted 

 and set on fire fragments of diamond, charcoal, 

 and plumbago, have been dispersed, as if they 

 had been evaporated platina, the hardest and 

 heaviest of the metals, has been melted as readily 

 aa wax in the flame of a candle the sapphire, 

 quartz, magnesia, lime, and the firmest com 

 pounds in nature, have been made to enter into 

 fusion. Its effects on the animal system are no 

 less surprising. When applied to a fowl or a 

 rabbit, immediately after life is extinct, it produ 

 ces the most strange and violent convulsions on 

 the nervous and muscular system, as if the vital 

 functions were again revived , and when applied 

 to the human body after death, the stimulus has 

 produced the most horrible contortions and gri 

 maces in the muscles of the head and face, and 

 the most rapid movements in the hands and feet. 



The galvanic agency enables us to account for 

 the following among other facts : Why porter 

 has a different and more pleasant taste, when 

 drunk out of a pewter vessel, than out of glass or 

 earthenware, why a silver spoon is discoloured 

 when used in eating eggs, why the limbs of 

 people, under amputation, are sometimes con 

 vulsed by the application of the instruments, 

 why pure mercury is oxydized when amalgama 

 ted with tin, why works of metal, which are 

 soldered together, soon tarnish in the places 

 where the metals are joined, and why the cop 

 per sheathing of ships, when fastened with iron 

 nails, is soon corroded about the place of con 

 tact. In all these cases a galvanic circle is 

 formed, which produces the effects. We have 

 reason to believe, that, in combination with the 

 discoveries which modern chymistry is daily un 

 folding, the agencies of this fluid will enable us to 

 carry the arts forward towards perfection, and to 

 trace the secret causes of some of the sublimest 

 phenomena of nature. 



VIII. Magnetism. This department of phi 

 losophy describes the phenomena and the pro 

 perties of the loadstone, or natural magnet. The 

 natural magnet is a hard dark-coloured mineral 

 body, and is usually found in iron mines. The 

 following are some of its characteristic proper 

 ties : 1. It attracts iron and steel, and all sub 

 stances which contain iron in its metallic state. 

 2. If a magnet be suspended by a thread, or 

 nicely poised on a pivot, or placed on a piece of 

 wood, and set to float in a basin of water, one 

 end will constantly point nearly towards the 

 north pole of the earth, and the other towards 

 the south ; and hence those parts of the magnet 

 have been called the north and south poles? 3. 

 When the north pole of one magnet is presented 

 near to the south pole of another, they will at 

 tract each other ; but if the north pole of one be 

 presented to the north pole of another, or a south 

 39 



pole to a south, they will repel each other. 4, 

 A magnet placed in such a manner as to be en 

 tirely at liberty, inclines one of its poles to tne 

 horizon, and of course elevates the other above 

 it. This property is called the dipping of the 

 magnet. 5. Magnets do not point directly north 

 and south ; but in different parts of the world 

 with a different declination eastward or westward 

 of the north ; it is also different at the same place 

 at different times. In London, and in most pla 

 ces of Great Britain, the magnetic needle, at 

 present, points about 24 degrees to the west of 

 north. For more than 160 years it has been 

 gradually declining from the north to the west : 

 but seems of late to have begun its declination to 

 the eastward. 6. Any magnet may be made to 

 communicate the properties now mentioned to 

 any piece of iron or steel. For example, by 

 gently rubbing a penknife with a magnet, it will 

 be immediately invested with the property of at 

 tracting needles, or small pieces of iron or steel. 

 7. Heat weakens the power of a magnet, and the 

 gradual addition of weight increases the mag 

 netic power. 8. The properties of the magnet 

 are not affected either by the presence or the ab 

 sence of air ; and the magnetic attraction is not 

 in the least diminished by the interposition of 

 any bodies except iron. A magnet will equally 

 affect the needle of a pocket compass when a 

 thick board is placed between them as when it is 

 removed. It has been lately discovered, that the 

 violet rays of the solar spectrum, when condensed 

 with a convex glass, and made to pass along a 

 piece of steel, have the power of communicating 

 to it the magnetic virtue. 



The cause which produces these singular 

 properties of the magnet has hitherto remained 

 a mystery ; but the knowledge of the polarity of 

 the magnet has been applied to a most important 

 practical purpose. By means of it, man has 

 now acquired the dominion of the ocean, and has 

 learned to trace his course through the pathless 

 deep to every region of the globe. There can 

 be little doubt that magnetism has an intimate 

 connexion with electricity, galvanism, light, 

 heat, and chymical action ; and the discoveries 

 which have been lately made, and the- experiments 

 which are now making by Morichini, Oersted, 

 Abraham, Hansteen, Barlow, Eeaufoy, and 

 Scoresby, promise to throw some light on this 

 mysterious agent, and on the phenomena of na 

 ture with which it is connected. 



Such is a faint outline of some of the inte 

 resting subjects which natural philosophy em 

 braces. Its relation to religion will appear from 

 the following considerations : 



1. Its researches have led to the invention of 

 machines, engines, and instruments of various 

 kinds, which augment the energies, increase tho 

 comforts, and promote the general improvement 

 of mankind; and these objects are inseparaniy 

 connected with the propagation of Christianity 



