Question: A hollow indiarubber ball full of air is suspended on one arm of a balance and weighed in air. The whole is then covered by the receiver of an air pump. Explain what will happen as the air in the receiver is exhausted.
Answer: The ball would expand and entirely fill the vessell, driving out all before it. The balance being of greater density than the rest would be the last to go, but in the end its inertia would be overcome and all would be expelled, and there would be a perfect vacuum. The ball would then burst, but you would not be aware of the fact on account of the loudness of a sound varying with the density of the place in which it is generated, and not on that in which it is heard.

A vast technology has been developed to prevent, reduce, or terminate exhausting labor and physical damage. It is now dedicated to the production of the most trivial conveniences and comfort.

Alcmaeon maintains that the bond of health is the 'equal balance' of the powers, moist and dry, cold and hot, bitter and sweet, and the rest, while the 'supremacy' of one of them is the cause of disease; for the supremacy of either is destructive. Illness comes aboutdirectly through excess of heat or cold, indirectly through surfeit or deficiency of nourishment; and its centre is either the blood or the marrow or the brain. It sometimes arises in these centres from external causes, moisture of some sort or environment or exhaustion or hardship or similar causes. Health on the other hand is the proportionate admixture of the qualities.

Even fairly good students, when they have obtained the solution of the problem and written down neatly the argument, shut their books and look for something else. Doing so, they miss an important and instructive phase of the work. ... A good teacher should understand and impress on his students the view that no problem whatever is completely exhausted.

I had gone on a walk on a fine Sabbath afternoon. I had entered the Green [of Glasgow] by the gate at the foot of Charlotte Street—had passed the old washing-house. I was thinking upon the engine at the time, and had gone as far as the herd's house, when the idea came into my mind that as steam was an elastic body it would rush into a vacuum, and if a communication were made between the cylinder and an exhausted vessel it would rush into it, and might be there condensed without cooling the cylinder. I then saw that I must get rid of the condensed steam and injection water if I used a jet, as in Newcomen's engine. Two ways of doing this occurred to me. First, the water might be run off by a descending pipe, if an outlet could be got at the depth of 35 or 36 feet, and any air might be extracted by a small pump. The second was to make the pump large enough to extract both water and air. ... I had not walked further than the Golf-house when the whole thing was arranged in my mind.
[In Robert Hart's words, a recollection of the description of Watt's moment of inspiration, in May 1765, for improving Thomas Newcomen's steam engine.]

In the light of knowledge attained, the happy achievement seems almost a matter of course, and any intelligent student can grasp it without too much trouble. But the years of anxious searching in the dark, with their intense longing, their alternations of confidence and exhaustion, and the final emergence into the light—only those who have experienced it can understand that.

Most people regard scientists as explorers … Imagine a handful of people shipwrecked on a strange island and setting out to explore it. One of them cuts a solitary path through the jungle, going on and on until he is exhausted or lost or both. He eventually returns to his companions, and they listen to him with goggling eyes as he describes what he saw; what he fell into, and what bit him. After a rest he demands more supplies and sets off again to explore the unknown. Many of his companions will be doing the same, each choosing his own direction and pursuing his pioneering path.

People who are unused to learning, learn little, and that slowly, while those more accustomed do much more and do it more easily. The same thing also happens in connection with research. Those who are altogether unfamiliar with this become blinded and bewildered as soon as their minds begin to work: they readily withdraw from the inquiry, in a state of mental fatigue and exhaustion, much like people who attempt to race without having been trained. He, on the other hand, who is accustomed to research, seeks and penetrates everywhere mentally, passing constantly from one topic to another; nor does he ever give up his investigation; he pursues it not merely for a matter of days, but throughout his whole life. Also by transferring his mind to other ideas which are yet not foreign to the questions at issue, he persists till he reaches the solution.

Science has thus, most unexpectedly, placed in our hands a new power of great but unknown energy. It does not wake the winds from their caverns; nor give wings to water by the urgency of heat; nor drive to exhaustion the muscular power of animals; nor operate by complicated mechanism; nor summon any other form of gravitating force, but, by the simplest means—the mere contact of metallic surfaces of small extent, with feeble chemical agents, a power everywhere diffused through nature, but generally concealed from our senses, is mysteriously evolved, and by circulation in insulated wires, it is still more mysteriously augmented, a thousand and a thousand fold, until it breaks forth with incredible energy.

Scientists alone can establish the objectives of their research, but society, in extending support to science, must take account of its own needs. As a layman, I can suggest only with diffidence what some of the major tasks might be on your scientific agenda, but … First, I would suggest the question of the conservation and development of our natural resources. In a recent speech to the General Assembly of the United Nations, I proposed a world-wide program to protect land and water, forests and wildlife, to combat exhaustion and erosion, to stop the contamination of water and air by industrial as well as nuclear pollution, and to provide for the steady renewal and expansion of the natural bases of life.

The fuel in the earth will be exhausted in a thousand or more years, and its mineral wealth, but man will find substitutes for these in the winds, the waves, the sun's heat, and so forth. (1916)

The next decade will perhaps raise us a step above despair to a cleaner, clearer wisdom and biology cannot fail to help in this. As we become increasingly aware of the ethical problems raised by science and technology, the frontiers between the biological and social sciences are clearly of critical importance—in population density and problems of hunger, psychological stress, pollution of the air and water and exhaustion of irreplaceable resources.

The rapid growth of industry, the ever increasing population and the imperative need for more varied, wholesome and nourishing foodstuff makes it all the more necessary to exhaust every means at our command to fill the empty dinner pail, enrich our soils, bring greater wealth and influence to our beautiful South land, which is synonymous to a healthy, happy and contented people.

The School of Physics could give us no suitable premises, but for lack of anything better, the Director permitted us to use an abandoned shed which had been in service as a dissecting room of the School of Medicine. Its glass roof did not afford complete shelter against rain; the heat was suffocating in summer, and the bitter cold of winter was only a little lessened by the iron stove, except in its immediate vicinity. There was no question of obtaining the needed proper apparatus in common use by chemists. We simply had some old pine-wood tables with furnaces and gas burners. We had to use the adjoining yard for those of our chemical operations that involved producing irritating gases; even then the gas often filled our shed. With this equipment we entered on our exhausting work. Yet it was in this miserable old shed that we passed the best and happiest years of our life.

These two orders of mountains [Secondary and Tertiary] offer the most ancient chronicle of our globe, least liable to falsifications and at the same time more legible than the writing of the primitive ranges. They are Nature's archives, prior to even the most remote records and traditions that have been preserved for our observant century to investigate, comment on and bring to the light of day, and which will not be exhausted for several centuries after our own.

These were errors of thought which cost me two years of excessively hard work, until I finally recognized them as such at the end of 1915, and after having ruefully returned to the Riemannian curvature, succeeded in linking the theory with the facts of astronomical experience.
In the light of knowledge attained, the happy achievement seems almost a matter of course, and any intelligent student can grasp it without too much trouble. But the years of anxious searching in the dark, with their intense longing, their alternations of confidence and exhaustion and the final emergence into the light—only those who have experienced it can understand it.

We are consuming our forests three times faster than they are being reproduced. Some of the richest timber lands of this continent have already been destroyed, and not replaced, and other vast areas are on the verge of destruction. Yet forests, unlike mines, can be so handled as to yield the best results of use, without exhaustion, just like grain fields.

Whenever Nature's bounty is in danger of exhaustion, the chemist has sought for a substitute. The conquest of disease has made great progress as a result of your efforts. Wherever we look, the work of the chemist has raised the level of our civilization and has increased the productive capacity of the nation. Waste materials, formerly cast aside, are now being utilized.