THE 



CIRCLE OF THE SCIENCES; 



A CYCLOPAEDIA 



OP 



EXPERIMENTAL, CHEMICAL, MATHEMATICAL, AND MECHANICAL PHILOSOPHY, 



AND NATURAL HISTORY. 



INTRODUCTION TO PHYSICS. 



AT a time when the applications of Science arc so numerous and highly appreciated, it would be a work of 

 supererogation to attempt to urge their value on the intelligent reader. It may, however, not be out of place, 

 to enquire by what means Experimental Philosophy has attained to its present high rank, either as an object of 

 study, or in its applications to the various requirements of civilised life. 



From the earliest ages, the phenomena of Nature must have been deeply investigated by intelligent observers. 

 The labours of Archimedes, Ptolemy, Thales, and others, evidence that there have been those in olden times who 

 delighted to enquire into the reasons and causes of the varied effects they witnessed. Indeed, Electricity a branch 

 of Science which, during the last half-century, has been applied to so many purposes was known in some of its effects 

 at least two thousand yean ago. Of Geometry and Astronomy, the oldest records extant prove that there were 

 many ardent followers. 



But, although a branch of Science has its origin in observation, still its progress is only effected by the mental 

 process of sound induction ; and in this department of Philosophy, the ancients were eminently deficient. Having 

 observed an effect, they, in most cases, hastily proceeded to seek a reason ; and having to contend with those 

 prejudice* of which Lord Bacon speaks so eloquently, they assigned causes which met special cases only. Hence 

 they were at last compelled to invent imaginary ones, which, as they only explained a few collateral effects, could 

 not be generalised. The result of this was, that no branch of Science, properly so called, was ever established : 

 guess-work and empiricism occupied the place of sound reasoning, and mists and mysticism were the final results of 

 ^h^jf researches in most instances. 



The Alchemists of the middle age* fall under the same category as the ancients. They had but one object in 

 view the conversion of the base into the precious metals ; hence every occurrence that presented itself to their 

 notice, which they conceived to be not relevant to their pursuit, was entirely neglected, or ridiculously philosophised 

 on. They preferred, indeed, to teach Nature, rather than to be taught by her ; and thus it can be matter of no 

 surprise that, under their auspices, Science made no progress. 



Eventually, however, a brighter intellectual day dawned. Experiment became the foundation ; fact the super- 

 structure ; whilst theory was but the scaffolding to the temple : and as soon as the system was adopted of tracing 

 causes from their effects, and of arranging such, that one theory might connect many causes, Experimental Science 

 advanced with rapid strides. From it* lofty abode in the time of Copernicus and Galileo, it has since descended, 

 and has become, as it were, the household god of even the very peasant of the land, and the proximate cause of most 

 of the comforts and conveniences of our existence. 



It is not, however, on account of the material advantages which Philosophy affords, that its pursuit is most to 

 be admired. Next to the great object of man's existence in this world the cultivation of religious sentiments the 

 expansion of the human mind immediately succeeds in value. And it is impossible to point out any other study 

 which more fully calls out and exercises the mental powers, than that of Nature. The perceptive faculties are 

 employed in investigation and observation ; the reasoning power in arranging causes ; and the reflective in focalising 

 the rays of light continually emitted : in fact, all the powers of the mind are thus braced and made ready for answer- 

 ing every call which can be made on them. 



In arranging the subjects included in the following pages, it has been attempted to make the simple to introduce 

 and prepare the way for the complex. By thus progressing from known to obscure matters, it is hoped that the way 

 of Science has been made plain, although no royal road has been opened out. The persistent attention of the reader 

 ha* becii assumed to have been granted by him ; and it is earnestly hoped that the demonstrations herein set forth, 

 may result in the comparatively easy solution of some of the most difficult, as well as the plainer problems in 

 Experimental and Natural Science. 



In pursuance of this plan, it will be necessary that we should enquire into those properties possessed by every 

 kind of matter ; and despite of all the sophisms of a class of metaphysicians, it will be impossible to define matter 

 otherwise than as that which can be weighed, measured, and perceived by the senses. The speculations of Berkeley 



TOL. i. B 



