PLEASURES OF SCIENCE. 45 



that these operations, so unlike to common eyes, when examined by 

 the lisrht of science, are the same, the rusting 1 of metals, the forma- 

 tion of acids, the burning- of inflammable bodies, the breathing of 

 animals, and the growth of plants by night. To know this is a 

 positive gratification. Is it not pleasing to find the same substance in 

 various situations extremely unlike each other ; to meet with fixed 

 air as the produce of burning, of breathing-, and of vegetation ; 

 to find that it is the choak-damp of mines, the bad air in the grotto 

 at Naples, the cause of death in neglected brewers' vats, and of the 

 brisk and acid flavour of Seltzer and other mineral spring's ? Nothing 1 

 can be less like than the working of a vast steam-engine, and the 

 crawling- of a fly upon the window. We find that these two operations 

 are performed by the same means, the weight of the atmosphere, and 

 that a sea-horse climbs the ice-hills by no other power. Can any thing 1 

 be more strange to contemplate ? Is there in all the fairy tales that 

 ever were fancied any thing more calculated to arrest the attention and 

 to occupy and to gratify the mind, than this most unexpected resem- 

 blance between things so unlike to the eyes of ordinary beholders ? 

 "What more pleasing occupation than to see uncovered and bared before 

 our eyes the very instrument and the process by which nature works ? 

 Then we raise our views to the structure of the heavens ; and are again 

 gratified with tracing accurate but most unexpected resemblances. Is 

 it not in the highest degree interesting to find, that the power which 

 keeps this earth in its shape, and in its path, wheeling round the sun, 

 extends over all the other worlds that compose the universe, and gives 

 to each its proper place and motion ; that this same power keeps the 

 moon in her path round our earth, and our earth in its path round the 

 sun, and each planet in its path ; that the same power causes the 

 tides upon our earth, and the peculiar form of the earth itself ; and 

 that, after all, it is the same power which makes a stone fall to the 

 ground ? To learn these things, and to reflect upon them, fills the 

 mind, and produces certain as well as pure gratification. 



But if the knowledge of the doctrines unfolded by science is pleasing, 

 so is the being able to trace the steps by which those doctrines are 

 investigated, and their truth demonstrated : indeed you cannot be said, 

 in any sense of the word, to have learnt them, or to know them, if you 

 have not so studied them as to perceive how they are proved. Without 

 this you never can expect to remember them long, or to understand them 

 accurately ; and that would of itself be reason enough for examining 

 closely the grounds they rest on. But there is the highest gratification 

 of all, in being able to see distinctly those grounds, so as to be satisfied 

 that a belief in the doctrines is well founded. Hence to follow a 

 demonstration of a grand mathematical truth to perceive how clearly 

 and how inevitably one step succeeds another, and how the whole steps 

 lead to the conclusion to observe how certainly and unerringly the 

 reasoning goes on from things perfectly self-evident, and by the smallest 

 addition at each step, every one being as easily taken after the one 

 before, as the first step of nil was, and yet the result being something 

 not only far from self-evident, but so general and strange, that you can 

 hardly believe it to be true, and are only convinced of it by geing over 



