DEVELOPMENTS IN PHYSICAL SCIENCE 451 
In studying this fourth state of matter we seem at length to have within 
our grasp and obedient to our control the little indivisible particles which with 
good warrant are supposed to constitute the physical basis of the universe. 
We have seen that in some of its properties radiant matter is as material as 
this table, whilst in other properties it almost assumes the character of radiant 
energy. We have actually touched the borderland where matter and force seem 
to merge into one another, the shadowy realm between known and unknown, 
which for me has always had peculiar temptations. I venture to think that 
the greatest scientific problems of the future will find their solution in this 
borderland, and even beyond; here, it seems to me, lie ultimate realities, subtle, 
far-reaching, wonderful. 
The developments of the last few years have demonstrated that no 
truer prophecy was ever uttered, and the prophet Crookes has lived to 
witness and to take a part in its fulfilment. 
The importance of the present rejuvenation of physical science does 
not consist alone in the abundance of the harvest. There have been 
abundant harvests in the past. Consider the decade which closed one 
hundred years ago. In 1798 Rumford boiled water by friction. In 
1799 Davy melted ice by friction in a vacuum and Laplace published 
his work on mechanics. In 1800 Volta constructed the Voltaic pue, 
Nicholson and Carlisle decomposed water, Davy discovered the proper- 
ties of laughing gas and Herschel discovered dark heat rays. In 1801 
Piazzi discovered the first asteroid, Ritter the chemical rays and Young 
the interference of light. In 1802 Wedgewood and Davy made sun 
pictures by the action of light on silver chloride, and Wollaston discov- 
ered dark lines in the sun’s spectrum. In 1808 Malus discovered polar- 
ization by reflection, Gay Lussac the combination of gases by multiple 
volumes and Dalton the law of multiple proportions. 
So great was the exhilaration and satisfaction produced by these 
discoveries that many scientists of that period appear to have become 
infected with something akin to the “ sixth decimal” delusion. “ Elec- 
tricity,” wrote the French scientist Haiiy, “ enriched by the labor of so 
many distinguished physicists seems to have reached the time when a 
science has no more important steps before it, and only leaves to those 
who cultivate it the hope of confirming the discoveries of their pre- 
decessors and of casting a brighter light on the truths revealed.” A 
statement which was almost immediately followed by the discoveries of 
Oersted, Ampére, Seebeck and Faraday. A statement which has been 
followed by the telegraph, the telephone, the dynamo, the motor, the 
electric light, the electric railway, the Rontgen rays and the wireless 
telegraph and telephone. 
If any one to-day is disposed to criticize the men of science of other 
times because of their limited view, their complacent opinions and their 
intolerance of all that did not agree with theories they considered estab- 
lished, let him first read and ponder over what One spake about motes 
and beams. 
