39 
all probability involved the rapid decline in the importance of the steam 
engine. I should not be surprised if many of those present should live to 
see the steam engine practically a thing of the past. To the eighteenth 
century also we must assign the discovery of galvanic electricity, as the 
famous frog experiments were made in 1790; practically, however, no de- 
velopment was made until Volta’s work attracted the attention of the 
scientific world. At the beginning of the nineteenth century, then, we find 
the subjects of greatest interest were the discoveries of Volta and the in- 
vention of the voltaic pile. Then followed almost immediately the discoy- 
ery of Nicholson and Carlisle of the decomposition of water by the voltaic 
current. This discovery was followed a few years later by the discovery 
of Sir Humphrey Davy of the decomposition of the alkalies and the separa- 
tion of metallic sodium and potassium. Thus the subject of electrolysis 
was fairly launched, and what it has grown to we will see later. 
Can there be some inter-relation between electricity and magnetism was 
now the query. The first positive answer seems to have been given by 
Romagnesi in a work published in 1805, but little or no notice appears to 
have been taken of this; certainly no progress was made in the subject till 
1820, when Oersted made his famous experiment before his class. By that 
experiment he proved that a wire carrying an electric current will, when 
properly placed, deflect a magnetic needle. The subject was almost im- 
mediately taken up by Ampere, and in a few months many of the impor- 
tant consequences which Oersted’s discovery involved were developed. Am- 
pere’s work on the action of currents on currents and on magnets, is class- 
ical and is still treated as part of the fundamental basis for the theory of 
electro-dynamics. An account of his work may therefore be found in al- 
most any of the numerous text-books on electricity. The conclusions 
reached by Ampere were confirmed by Weber, by a series of much more 
refined experiments. To Weber also we owe improvements in galyano- 
meters. The same year marks the discovery by Arago that a current can 
not only deflect a magnet. but that it is capable of producing one by mag- 
netizing steel needles. The further discovery was made four years later 
by Sturgeon that soft iron, although incapable of making a strong perma- 
nent magnet, is much more susceptible to magnetization by the electric 
current. Arago also made about this time the important discovery that if 
a needle be suspended above a copper disc and the dise rotated, the needle 
will be dragged round with the disc. This was not explained for some 
years, but seems to have been the first discovery of induced currents. 
