21 8 GREAT MEN OF SCIENCE 



piece of wire passing beneath a magnetic needle set in the 

 meridian, to enable stronger currents to be estimated quan- 

 titatively according to the amount of the deflection of the 

 needle. Oersted's publication already showed the direct 

 way to deal with weaker currents, namely to bend the con- 

 ductor in a suitable manner several times round the needle, 

 which led, already in the same year 1820, to the 'multiplier' 

 provided with many turns of wire surrounding the needle 

 (Schweigger in Halle, and Poggendorff in Berlin). The 

 single turns of wire were at first insulated with resin or 

 sealing wax; but silk covered wires were soon introduced. 

 Among all those who immediately busied themselves with the 

 new field. Ampere was pre-eminent by the depth of the 

 ideas and the importance of the further discoveries, which he 

 developed. 



PIERRE SIMON LAPLACE {1749-1827) 

 ANDRfi MARIE AMP£RE {1775-1836) 



The French Academy, which had already produced work of 

 such importance in the investigation of light by Fresnel, 

 again placed itself at first in the forefront, thanks to Ampere, 

 in respect of Oersted's discovery. The high reputation 

 of this Academy was certainly favourable both to Fresnel's 

 and to Ampere's activity, and this reputation it owed to a 

 number of great intellects among its members, over whom 

 presided Laplace, at that time seventy years of age, and on 

 the pinnacle of fame. 



Laplace came from poor parents in Normandy. He at- 

 tended a military school, but was soon noticed at a very early 

 age in the circles of the Paris Academy on account of his 

 eminent mathematical gifts, whereby he attained to in- 

 creasingly important offices, with influence on education, and 



