(source) 
Silvanus Phillips Thompson,
(19 Jun 1851  12 Jun 1916)

Science Quotes by Silvanus Phillips Thompson, (7 quotes)
Again and again in reading even his [William Thomson] most abstract writings one is struck by the tenacity with which physical ideas control in him the mathematical form in which he expressed them. An instance of this is afforded by â€¦ an example of a mathematical result that is, in his own words, â€śnot instantly obvious from the analytical form of my solution, but which we immediately see must be the case by thinking of the physical meaning of the result.â€ť
— Silvanus Phillips Thompson,
Not seldom did he [Sir William Thomson], in his writings, set down some mathematical statement with the prefacing remark â€śit is obvious thatâ€ť to the perplexity of mathematical readers, to whom the statement was anything but obvious from such mathematics as preceded it on the page. To him it was obvious for physical reasons that might not suggest themselves at all to the mathematician, however competent.
— Silvanus Phillips Thompson,
Once when lecturing to a class he [Lord Kelvin] used the word â€śmathematician,â€ť and then interrupting himself asked his class: â€śDo you know what a mathematician is?â€ť Stepping to the blackboard he wrote upon it:â€” [an integral expression equal to the square root of pi]
Then putting his finger on what he had written, he turned to his class and said: â€śA mathematician is one to whom that is as obvious as that twice two makes four is to you. Liouville was a mathematician.â€ť
Then putting his finger on what he had written, he turned to his class and said: â€śA mathematician is one to whom that is as obvious as that twice two makes four is to you. Liouville was a mathematician.â€ť
— Silvanus Phillips Thompson,
Tait once urged the advantage of Quaternions on Cayley (who never used them), saying: â€śYou know Quaternions are just like a pocketmap.â€ť â€śThat may be,â€ť replied Cayley, â€śbut youâ€™ve got to take it out of your pocket, and unfold it, before itâ€™s of any use.â€ť And he dismissed the subject with a smile.
— Silvanus Phillips Thompson,
The following is one of the many stories told of â€śold Donald McFarlaneâ€ť the faithful assistant of Sir William Thomson.
The father of a new student when bringing him to the University, after calling to see the Professor [Thomson] drew his assistant to one side and besought him to tell him what his son must do that he might stand well with the Professor. â€śYou want your son to stand weel with the Profeessorr?â€ť asked McFarlane. â€śYes.â€ť â€śWeel, then, he must just have a guid bellyful oâ€™ mathematics!â€ť
The father of a new student when bringing him to the University, after calling to see the Professor [Thomson] drew his assistant to one side and besought him to tell him what his son must do that he might stand well with the Professor. â€śYou want your son to stand weel with the Profeessorr?â€ť asked McFarlane. â€śYes.â€ť â€śWeel, then, he must just have a guid bellyful oâ€™ mathematics!â€ť
— Silvanus Phillips Thompson,
The following story (here a little softened from the vernacular) was narrated by Lord Kelvin himself when dining at Trinity Hall:
A certain rough Highland lad at the university had done exceedingly well, and at the close of the session gained prizes both in mathematics and in metaphysics. His old father came up from the farm to see his son receive the prizes, and visited the College. Thomson was deputed to show him round the place. â€śWeel, Mr. Thomson,â€ť asked the old man, â€śand what may these mathematics be, for which my son has getten a prize?â€ť â€śI told him,â€ť replied Thomson, â€śthat mathematics meant reckoning with figures, and calculating.â€ť â€śOo ay,â€ť said the old man, â€śheâ€™ll haâ€™ getten that fraâ€™ me: I were ever a braw hand at the countinâ€™.â€ť After a pause he resumed: â€śAnd what, Mr. Thomson, might these metapheesics be?â€ť â€śI endeavoured,â€ť replied Thomson, â€śto explain how metaphysics was the attempt to express in language the indefinite.â€ť The old Highlander stood still and scratched his head. â€śOo ay: may be heâ€™ll haâ€™ getten that fraâ€™ his mither. She were aye a bletherinâ€™ body."
A certain rough Highland lad at the university had done exceedingly well, and at the close of the session gained prizes both in mathematics and in metaphysics. His old father came up from the farm to see his son receive the prizes, and visited the College. Thomson was deputed to show him round the place. â€śWeel, Mr. Thomson,â€ť asked the old man, â€śand what may these mathematics be, for which my son has getten a prize?â€ť â€śI told him,â€ť replied Thomson, â€śthat mathematics meant reckoning with figures, and calculating.â€ť â€śOo ay,â€ť said the old man, â€śheâ€™ll haâ€™ getten that fraâ€™ me: I were ever a braw hand at the countinâ€™.â€ť After a pause he resumed: â€śAnd what, Mr. Thomson, might these metapheesics be?â€ť â€śI endeavoured,â€ť replied Thomson, â€śto explain how metaphysics was the attempt to express in language the indefinite.â€ť The old Highlander stood still and scratched his head. â€śOo ay: may be heâ€™ll haâ€™ getten that fraâ€™ his mither. She were aye a bletherinâ€™ body."
— Silvanus Phillips Thompson,
The seemingly useless or trivial observation made by one worker leads on to a useful observation by another: and so science advances, â€ścreeping on from point to point.â€ť
— Silvanus Phillips Thompson,
See also:
 19 Jun  short biography, births, deaths and events on date of Thompson's birth.