[To elucidate using models] the different combining powers in elementary atoms, I … select my illustrations from that most delightful of games, croquet. Let the croquet balls represent our atoms, and let us distinguish the atoms of different elements by different colours. The white balls are hydrogen, the green ones chlorine atoms; the atoms of fiery oxygen are red, those of nitrogen, blue; the carbon atoms, lastly, are naturally represented by black balls. But we have, in addition, exhibit the different combining powers of these atoms … by screwing into the balls a number of metallic arms (tubes and pins), which correspond respectively to the combining powers of the atoms represented … to join the balls … in imitation of the atomic edifices represented.

Nature is curious, and such worke may make,
That our dull sense can never finde, but scape.
For Creatures, small as Atomes, may be there,
If every Atome a Creatures Figure beare.
If foure Atomes a World can make, then see
What severall Worlds might in an Eare--ring bee:
For Millions of these Atomes may bee in
The Head of one Small, little, Single Pin.
And if thus Small, then Ladies may well weare
A World of Worlds, as Pendents in each Eare.

As the nineteenth century drew to a close, scientists could reflect with satisfaction that they had pinned down most of the mysteries of the physical world: electricity, magnetism, gases, optics, acoustics, kinetics and statistical mechanics … all had fallen into order before them. They had discovered the X ray, the cathode ray, the electron, and radioactivity, invented the ohm, the watt, the Kelvin, the joule, the amp, and the little erg.

Ecologically speaking, a spilt tanker load is like sticking a safety pin into an elephant’s foot. The planet barely notices. After the Exxon Valdez accident in Alaska the oil company spent billions tidying up the coastline, but it was a waste of money because the waves were cleaning up faster than Exxon could. Environmentalists can never accept the planet’s ability to self-heal.

I can remember … starting to gather all sorts of things like rocks and beetles when I was about nine years old. There was no parental encouragement—nor discouragement either—nor any outside influence that I can remember in these early stages. By about the age of twelve, I had settled pretty definitely on butterflies, largely I think because the rocks around my home were limited to limestone, while the butterflies were varied, exciting, and fairly easy to preserve with household moth-balls. … I was fourteen, I remember, when … I decided to be scientific, caught in some net of emulation, and resolutely threw away all of my “childish” specimens, mounted haphazard on “common pins” and without “proper labels.” The purge cost me a great inward struggle, still one of my most vivid memories, and must have been forced by a conflict between a love of my specimens and a love for orderliness, for having everything just exactly right according to what happened to be my current standards.

I think people get it upside down when they say the unambiguous is the reality and the ambiguous is merely uncertainty about what is really unambiguous. Let’s turn it around the other way: the ambiguous is the reality and the unambiguous is merely a special case of it, where we finally manage to pin down some very special aspect.

Isn’t it weird how scientists can imagine all the matter of the universe exploding out of a dot smaller than the head of a pin, but they can’t come up with a more evocative name for it than “The Big Bang”? … [I’d call it] “The Horrendous Space KABLOOUIE!”

Jefferson refused to pin his hopes on the occasional success of honest and unambitious men; on the contrary, the great danger was that philosophers would be lulled into complacence by the accidental rise of a Franklin or a Washington. Any government which made the welfare of men depend on the character of their governors was an illusion.

Looking through the telescope, one saw a circle of deep blue and the little round planet swimming in the field. It seemed such a little thing, so bright and small and still, faintly marked with transverse stripes, and slightly flattened from the perfect round. But so little it was, so silvery warm—a pin’s-head of light! It was as if it quivered, but really this was the telescope vibrating with the activity of the clockwork that kept the planet in view.
As I watched, the planet seemed to grow larger and smaller and to advance and recede, but that was simply that my eye was tired. Forty millions of miles it was from us—more than forty millions of miles of void. Few people realise the immensity of vacancy in which the dust of the material universe swims.

Most pilots learn, when they pin on their wings and go out and get in a fighter, especially, that one thing you don’t do, you don’t believe anything anybody tells you about an airplane.

One and all
We lend an ear—nay, Science takes thereto—
Encourages the meanest who has racked
Nature until he gains from her some fact,
To state what truth is from his point of view,
Mere pin-point though it be: since many such
Conduce to make a whole, she bids our friend
Come forward unabashed and haply lend
His little life-experience to our much
Of modern knowledge.

Physicians get neither name nor fame by the pricking of wheals or the picking out thistles, or by laying of plaisters to the scratch of a pin; every old woman can do this. But if they would have a name and a fame, if they will have it quickly, they must do some great and desperate cures. Let them fetch one to life that was dead; let them recover one to his wits that was mad; let them make one that was born blind to see; or let them give ripe wits to a fool: these are notable cures, and he that can do thus, if he doth thus first, he shall have the name and fame he deserves; he may lie abed till noon.

Shoe leather epidemiology.
[Langmuir stressed that investigators go into the field to collect their own data and directly view the locale of a public health problem. His graduates wore lapel pins of a shoe with a hole in the sole.]

The conundrum that baffled Medieval philosophers, How many angels can dance on the head of a pin?, can have only one correct answer: All of them.

The more important fundamental laws and facts of physical science have all been discovered, and these are now so firmly established that the possibility of their ever being supplanted in consequence of new discoveries is exceedingly remote. Nevertheless, it has been found that there are apparent exceptions to most of these laws, and this is particularly true when the observations are pushed to a limit, i.e., whenever the circumstances of experiment are such that extreme cases can be examined. Such examination almost surely leads, not to the overthrow of the law, but to the discovery of other facts and laws whose action produces the apparent exceptions. As instances of such discoveries, which are in most cases due to the increasing order of accuracy made possible by improvements in measuring instruments, may be mentioned: first, the departure of actual gases from the simple laws of the so-called perfect gas, one of the practical results being the liquefaction of air and all known gases; second, the discovery of the velocity of light by astronomical means, depending on the accuracy of telescopes and of astronomical clocks; third, the determination of distances of stars and the orbits of double stars, which depend on measurements of the order of accuracy of one-tenth of a second-an angle which may be represented as that which a pin's head subtends at a distance of a mile. But perhaps the most striking of such instances are the discovery of a new planet or observations of the small irregularities noticed by Leverrier in the motions of the planet Uranus, and the more recent brilliant discovery by Lord Rayleigh of a new element in the atmosphere through the minute but unexplained anomalies found in weighing a given volume of nitrogen. Many other instances might be cited, but these will suffice to justify the statement that “our future discoveries must be looked for in the sixth place of decimals.”

The publication of the Darwin and Wallace papers in 1858, and still more that of the 'Origin' in 1859, had the effect upon them of the flash of light, which to a man who has lost himself in a dark night, suddenly reveals a road which, whether it takes him straight home or not, certainly goes his way. That which we were looking for, and could not find, was a hypothesis respecting the origin of known organic forms, which assumed the operation of no causes but such as could be proved to be actually at work. We wanted, not to pin our faith to that or any other speculation, but to get hold of clear and definite conceptions which could be brought face to face with facts and have their validity tested. The 'Origin' provided us with the working hypothesis we sought.

The rudest numerical scales, such as that by which the mineralogists distinguish different degrees of hardness, are found useful. The mere counting of pistils and stamens sufficed to bring botany out of total chaos into some kind of form. It is not, however, so much from counting as from measuring, not so much from the conception of number as from that of continuous quantity, that the advantage of mathematical treatment comes. Number, after all, only serves to pin us down to a precision in our thoughts which, however beneficial, can seldom lead to lofty conceptions, and frequently descend to pettiness.

This Academy [at Lagado] is not an entire single Building, but a Continuation of several Houses on both Sides of a Street; which growing waste, was purchased and applied to that Use.
I was received very kindly by the Warden, and went for many Days to the Academy. Every Room hath in it ' one or more Projectors; and I believe I could not be in fewer than five Hundred Rooms.
The first Man I saw was of a meagre Aspect, with sooty Hands and Face, his Hair and Beard long, ragged and singed in several Places. His Clothes, Shirt, and Skin were all of the same Colour. He had been Eight Years upon a Project for extracting Sun-Beams out of Cucumbers, which were to be put into Vials hermetically sealed, and let out to warm the Air in raw inclement Summers. He told me, he did not doubt in Eight Years more, that he should be able to supply the Governor's Gardens with Sunshine at a reasonable Rate; but he complained that his Stock was low, and interested me to give him something as an Encouragement to Ingenuity, especially since this had been a very dear Season for Cucumbers. I made him a small Present, for my Lord had furnished me with Money on purpose, because he knew their Practice of begging from all who go to see them.
I saw another at work to calcine Ice into Gunpowder; who likewise shewed me a Treatise he had written concerning the Malleability of Fire, which he intended to publish.
There was a most ingenious Architect who had contrived a new Method for building Houses, by beginning at the Roof, and working downwards to the Foundation; which he justified to me by the life Practice of those two prudent Insects the Bee and the Spider.
In another Apartment I was highly pleased with a Projector, who had found a device of plowing the Ground with Hogs, to save the Charges of Plows, Cattle, and Labour. The Method is this: In an Acre of Ground you bury at six Inches Distance, and eight deep, a quantity of Acorns, Dates, Chestnuts, and other Masts or Vegetables whereof these Animals are fondest; then you drive six Hundred or more of them into the Field, where in a few Days they will root up the whole Ground in search of their Food, and make it fit for sowing, at the same time manuring it with their Dung. It is true, upon Experiment they found the Charge and Trouble very great, and they had little or no Crop. However, it is not doubted that this Invention may be capable of great Improvement.
I had hitherto seen only one Side of the Academy, the other being appropriated to the Advancers of speculative Learning.
Some were condensing Air into a dry tangible Substance, by extracting the Nitre, and letting the acqueous or fluid Particles percolate: Others softening Marble for Pillows and Pin-cushions. Another was, by a certain Composition of Gums, Minerals, and Vegetables outwardly applied, to prevent the Growth of Wool upon two young lambs; and he hoped in a reasonable Time to propagate the Breed of naked Sheep all over the Kingdom.

We must protect each other against the attacks of those self-appointed watchdogs of patriotism now abroad in the land who irresponsibly pin red labels on anyone whom they wish to destroy. ... [Academic professionals are the only person competant to differentiate between honest independents and the Communists.] This is our responsibility. It is not a pleasant task. But if it is left to outsiders, the distinction is not likely to be made and those independent critics of social institutions among us who are one of the glories of a true university could be silenced.

We want greater venturesomeness. We have sat on the river bank and caught catfish with pin hooks. The time has come to harpoon a whale. And if we must gratify any human tendency to appropriate, let us take an empire.