AN ANCIENT SCIENTIST. 835 



the ordinary scientific argument from experience, and, although not 

 strictly logical, is an expression of the conviction, common to every 

 student of Nature, of the continuity and permanence of physical law. 

 This conviction is not supported by arguments, but is built up slowly 

 and surely by the daily observation of Nature's working and of the 

 never-failing fulfillment of her laws. Our author's reasoning, there- 

 fore, is calculated rather to convince the man of science than the mere 

 logician. 



Having established this principle, he goes on to state the converse, 

 that matter is never annihilated. For, he argues, since nothing can 

 be created, a continual unreplaced loss would have been going on, 

 which in the infinite course of past time would have left nothing of 

 the universe at all. Here, again, he shows that he has the scientific 

 conviction of the uniforriiity of nature. An objector might have 

 said, " Though there has been no loss, no annihilation in time past, 

 how do you know that there will be none in time future ? " This 

 argument, though unanswerable, is incapable of producing conviction 

 in a scientific mind. Such an argument, as Tyndall remarks in his 

 " Fragments of Science," is employed by the spiritualists in regai"d to 

 the sun's failing to rise on the morrow. " Before such a state of 

 mind," says he, " the scientific intellect is absolutely powerless." The 

 convictions that rise from uniform experience in the pursuit of physi- 

 cal studies are unassailable by any reasoning short of a mathematical 

 demonstration. 



Lucretius adds that, in many cases of apparent annihilation, mat- 

 ter is but lost to grow again in another form. He instances the rain 

 whose drops fall upon the ground and are scattered, but appear again 

 in the blooming tree which shelters beneath its branches flocks and 

 herds and the race of men. Here, as often with this poet, a beautiful 

 episode crops out in the midst of his philosophical argument. Indeed, 

 it is one of his characteristics, and forms his claim to be considered a 

 great poet, that, combined with his appreciation of the order and con- 

 tinuity of nature, he has a fervent love for all its aspects of beauty 

 and life. Often he turns aside to tell of frisking lambs and babbling 

 brooks, and trees that spread their branches far and wide. He seems 

 to have loved nature in all its forms, and to have devoted to it all the 

 w^ealth of his intellect and imagination. He closes this argument 

 with the celebrated saying, " Nature builds up one thing by means 

 of another, and suffers nothing to be born except another die." 



These two propositions, that nothing is created and nothing de- 

 stroyed, are the primary postulates upon which as a foxmdation he 

 builds the whole theory of atoms. His first step is to show that there 

 are bodies, which, though invisible, are yet appreciable through the 

 senses. The air, he argues, must consist of solid particles in as true 

 a sense as water, for water itself can not produce greater effects than 

 violent winds. There are, too, other particles of matter which affect 



