Thomas Young Quotes

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.

The fundamental doctrines of motion have [herein]... been more immediately referred to axioms simply mathematical than has hitherto been usual; and the application of these doctrines to practical purposes has [herein]... been facilitated.

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.

There is no study more difficult than that of physic: it exceeds, as a science, the comprehension of the human mind: and those who blunder onwards, without attempting to understand what they see, are often very nearly on a level with those, who depend too much on imperfect generalisations, applied to facts, which can scarcely be subjected to any well marked analogy. Hence it may happen, that talents and labour may become useless for want of a proper direction... To assist in furnishing the student with a sufficient direction... is the principal object of this work.

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.

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.

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.

The passive of all kinds has been very fully investigated, and many new conclusions have been formed respecting it, which are of immediate importance to the architect and to the engineer, and which appear to contradict the results of some very elaborate calculations.

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...

have enumerated, in a compendious and systematical form, the principal facts which have been discovered with respect to galvanic electricity; and I have fortunately been able to profit by Mr. Davy's most important experiments, which have lately been communicated to the , and which have already given to this branch of science a much greater perfection, and a far greater extent, than it before possessed.