tween mere information and education was pointed out, and Mr. Scott remarked that the object of the Working Man's College was that those who were led to inquire into the great principles and the methods by which the grand hereditary accumulations of human knowledge had taken place, that had been handed down from century to century, might have somebody at hand who was willing to help them to such knowledge. A greater diffusion of education would influence our social condition. It had been proposed to give the electoral franchise on the ground of education. It seemed a very reasonable thing that if persons said "the reason why we give the franchise to certain men of property is because that supposes a certain amount of education," it was reasonable to answer "then when you can ascertain that there is an equal or superior amount of education, why not then confer the franchise?" Professor Scott concluded by thanking his auditors for their attention, for which he was grateful, because he believed it had been the expression of their confidence in his good will to the object and those who were personally interested in it.

PHYSICAL SCIENCE.

BY HENRY E. ROSCOE, Esq, B.A., PH.D. F. C.S.

[The Inaugural Address delivered to the Students of Owens College, Manchester, on the opening of the Session of 1857-8.]

THE grand distinguishing feature of the progress of civilisation in our times, as compared with that of any preceding age, is, without question, the ever increasing knowledge of nature which we are now acquiring. Our great progress consists in calling to our aid the knowledge we have gained of the inanimate forces of nature, in making them work for us, thus freeing man from mechanical labour, and permitting him to exercise his high and true vocation-that of a thinking being. To place this characteristic of our age strikingly before us, we need only contrast our steam ships, railways, telegraphs, reaping machines, steam ploughs, cotton mills, and a host of other modes of applying force, with the means adopted for a similar purpose in past times. Our age is, then, especially the age of physical science, for it is to this branch of human knowledge that we owe all these inestimable benefits.

The advantages accruing from the employment of the inanimate forces to produce effects for which human labour was formerly exclusively used, is, however, not confined to the liberation of the mental energy of man, for the amount of mechanical effect which we can produce by the inanimate forces is far greater than that which animal exertion can create. In order to see this, we need only compare for an instant the mechanical effect produced

by the combustion of coal with that brought out by men's labour. To use the words of Sir John Herschell, "It is well known to modern engineers that there is virtue in a bushel of coals, properly consumed, to raise seventy millions of pounds a foot high. This is actually the average effect of an engine now working in Cornwall. Let us pause a moment and consider what this is equivalent to in matters of practice. The ascent of Mont Blanc is considered, and with justice, as the most toilsome feat which a man can perform in two days. The combustion of two pounds of coal would put him on the summit. The Menai Bridge, one of the most stupendous works of art which have been raised by man in modern ages, consists of a mass of iron not less than four million pounds in weight, suspended at a height of about 120 feet above the sea. The consumption of seven bushels of coal would raise it to the place where it hangs." If we thus compare the work effected by an engine fed with a known quantity of fuel with that done in a day by a man of average strength, it is easy to express the value of human labour in pounds of coal. By a simple calculation it is found that if the whole of the coal annually raised in England were used in working steam engines, a number of labourers three thousand times as numerous as the inhabitants of these islands would have to be employed to effect the same amount of work; or, to put it in another way, the force represented in the coal raised in England is equivalent to an army of three thousand men for each inhabitant of our country.

I might multiply, indefinitely, these illustrations of the immense source of energy which the inanimate forces offer to us; my object, however, in the few words which I now address to you will be to endeavour most cursorily to trace the progress of physical science from its birth to its present state of development, or rather, perhaps, to sketch out a few of the chief principles involved in this progress. The commencement of the existence of physical science dates from the latter

half of the 16th century, when Lord Bacon distinctly enunciated the true principle of scientific investigation. Bacon showed that the results of scientific reasoning can only be sound and of value when based upon certain and well-ascertained facts; that the observation of what occurs around us constitutes the only true foundation upon which the fabric of science can rest, and that à priori reasoning must, in matters of natural science, be but sparingly employed. These great truths had already been partially announced by the first Bacon three hundred years before, but Lord Bacon placed them in their true light, and was the first to see plainly and proclaim loudly that a new era for science had arrived, in which the inward contemplations and rash generalisations of the former schools must give place to patient and laborious observation, and the gradual ascent from individual facts to collections of facts, to laws and general laws. At the end of the 16th and beginning of the 17th century came that glorious trio of philosophers, Galileo, Kepler, and Newton, to whom we are indebted for the keystone of science. The immortal labours of these men made us first acquainted with the fact that natural phenomena depend upon unchanging laws; that a never varying relation exists between the innumerable changes which we behold, and hence that an investigation of these occurrences is possible. Without the certainty that under similar conditions the same phenomena will be observed, experimental science cannot exist. The great discoveries of these three founders of modern science paved the way for all the future seekers after truth, and for all the practical applications of this truth. Newton's discovery of the mighty laws which rule the motions of suns and systems of suns, as well as the smallest particles of matter, was a necessary precursor of the railway and electric telegraph. Until the laws regulating the simple motions of bodies are fully understood we cannot expect to arrive at a knowledge of the more complicated phenomena of

nature.

The great impulse thus given to the study of natural phenomena by the proclamation of this true method of scientific inquiry, and the results obtained by the first investigators who followed out this method, was soon rendered visible by the rapid progress made in the succeeding century. Notwithstanding the comparatively perfect state which many branches of natural science soon arrived at, some still remained in the most primitive stage of development. Chemistry, for instance, had as yet no guiding principle, no fixed or general laws by which its phenomena could be classed or explained. The first great landmark in our science was not observed till towards the end of the 18th century, almost within the memory of living men,-when Lavoisier first proved the great truth of the indestructibility of matter. Before his time chemists explained the combustion of a substance, the rusting or calcination, as they called it, of a metal, by supposing that the metal was a compound of the metallic rust with a combustible principle, which they called phlogiston, and that in burning this principle escaped, leaving behind the pure substance. Lavoisier overthrew this doctrine simply by weighing the metal before and after burning. He found that the burnt metal weighed more than the metal itself, and that therefore in burning it could not have lost anything, but that, on the contrary it must have gained something; and he showed that this something was the atmospheric oxygen. Lavoisier also proved that the atmosphere lost as much after burning as the metal had gained, and from this he drew the general conclusion that matter, though it may become invisible, cannot be destroyed; that the weight of matter is a property which always remains.

constant.

From the time of the publication of these facts and views we may date the commencement of modern chemistry. The light which the adoption of this single consideration of weight shed upon the explanation of chemical facts was most brilliant; apparently complicated phenomena became simple, and to the impetus