Thomas Young Quotes

The theory of the tides has been reduced into an extremely simple form, which appears to agree better with all the phenomena, than the more intricate calculations which they have commonly been supposed to require.

I have... begun to collect materials for a work... relating to every department of medical knowledge: ...it will be comparatively more concise than these lectures, in proportion to what has been said and written respecting physic, but, I hope, much more complete, with regard to all that is known with certainty, and can be applied with utility.

It may hereafter be considered how far the excellent experiments of Count Rumford, which tend very greatly to weaken the evidence of the modern doctrine of heat, may be more or less favourable to one or the other system of light and colours.

A permanent alteration of form limits the strength of materials with regard to practical purposes, almost as much as fracture; since, in general, the force which is capable of producing this effect is sufficient, with a small addition, to increase it till fracture takes place.

When I was a boy, I thought myself a man. Now that I am a man, I find myself a boy.

The historical part of the work can scarcely be called new, but several of the circumstances, which are related, have escaped the notice of former writers on the history of the sciences.

Physic is one of those departments, in which there is frequent necessity for the exercise of an incommunicable faculty of judgment, and a sagacity, which may be called transcendental, as extending beyond the simple combination of all that can be taught by precept. Nor is there any other mode of cultivating these powers, than by pursuing a much more extensive range of elementary study, than appears, to a common and superficial observer, to be in any way connected with the immediate objects of the profession.

In the astronomical and physical division of the work, will be found a general rule for determining the correction on account of aberration; a comparison of observations on the ; a table of the order of electrical excitation; a chart of the variation of the compass, and of the ; formulae for finding the heat of summer and winter; remarks on the theory of the winds; and a comparative table of all the mechanical properties of a variety of natural bodies.

The well known elevation of the pitch of wind instruments, in the course of playing, sometimes amounting to half a note, is not, as is commonly supposed, owing to any expansion of the instrument, for this should produce a contrary effect, but to the increased warmth of the air in the tube.

[T]he lectures... may be expected to remain tolerably commensurate to the state of the sciences for a much longer period; since, in investigations so intimately connected with mathematical principles, the essential improvements will always bear a very small proportion to the number of innovations. ...the references, which it contains, are... sufficient to lead those, who may consult the passages quoted, to the works of every author of eminence that has treated of the respective subjects.

With respect to the cohesion and of liquids, I have had the good fortune to anticipate Mr. Laplace in his late researches, and I have endeavoured to show, that my assumptions are more universally applicable to the facts, than those which that justly celebrated mathematician has employed.

Besides these improvements,... there are others,... which may... be interesting to those... engaged in those departments... Among these may be ranked, in the division of mechanics, properly so called, a simple demonstration of the law of the force by which a body revolves in an ellipsis; another of the properties of al pendulums; an examination of the mechanism of animal motions; a comparison of the measures and weights of different countries; and a convenient estimate of the effect of human labour: with respect to architecture, a simple method of drawing the outline of a column: an investigation of the best forms for arches; a determination of the curve which affords the greatest space for turning; considerations on the structure of the joints employed in carpentry, and on the firmness of wedges; and an easy mode of forming a kirb roof: for the purposes of machinery of different kinds, an arrangement of bars for obtaining rectilinear motion; an inquiry into the most eligible proportions of wheels and s; remarks on the friction of wheel work, and of balances; a mode of finding the form of a tooth for impelling a pallet without friction; a chronometer for measuring minute portions of time; a clock ; a calculation of the effect of temperature on steel springs; an easy determination of the best line of draught for a carriage; an investigation of the resistance to be overcome by a wheel or roller; and an estimation of the ultimate pressure produced by a blow.

In the department of , the phenomena of halos and parhelia have been explained, upon principles not entirely new, but long forgotten: the functions of the eye have been minutely examined, and the mode of its accommodation to the perception of objects at different distances ascertained: the various phenomena of coloured light have been copiously described, and accurately represented by coloured plates; and some new cases of the production of colours have been pointed out, and have been referred to the general law of double lights, by which a great variety of the experiments of former opticians have also been explained; and this law has been applied to the establishment of a theory of the nature of light, which satisfactorily removes almost every difficulty that has hitherto attended the subject.

With respect to the mathematical part of optics, the curvature of the images, formed by lenses and mirrors, has been correctly investigated, and the inaccuracy of some former estimations has been demonstrated.

It is surprising that so great a mathematician as Dr. Smith could have entertained for a moment, an idea that the vibrations constituting different sounds should be able to cross each other in all directions, without affecting the same individual particles of air by their joint forces: undoubtedly they cross, without disturbing each other's progress; but this can be no otherwise effected than by each particle's partaking of both motions. If this assertion stood in need of any proof, it might be amply furnished by the phenomena of beats, and of the grave harmonics observed...