All fresh meat is eaten in a state of decay. The process may not have proceeded so far that the dull human nose can discover it, but a carrion bird or a carrion fly can smell it from afar.

As the sense of smell is so intimately connected with that of taste, it is not surprising that an excessively bad odour should excite wretching or vomitting in some persons.

I happen to be a kind of monkey. I have a monkeylike curiosity that makes me want to feel, smell, and taste things which arouse my curiosity, then to take them apart. It was born in me. Not everybody is like that, but a scientific researchist should be. Any fool can show me an experiment is useless. I want a man who will try it and get something out of it.

The Qualities then that are in Bodies rightly considered, are of Three sorts.
First, the Bulk, Figure, Number, Situation, and Motion, or Rest of their solid Parts; those are in them, whether we perceive them or no; and when they are of that size, that we can discover them, we have by these an Idea of the thing, as it is in it self, as is plain in artificial things. These I call primary Qualities.
Secondly, The Power that is in any Body, by Reason of its insensible primary Qualities, to operate after a peculiar manner on any of our Senses, and thereby produce in us the different Ideas of several Colours, Sounds, Smells, Tastes, etc. These are usually called sensible Qualities.
Thirdly, The Power that is in any Body, by Reason of the particular Constitution of its primary Qualities, to make such a change in the Bulk, Figure, Texture, and Motion of another Body, as to make it operate on our Senses, differently from what it did before. Thus the Sun has a Power to make Wax white, and Fire to make Lead fluid. These are usually called Powers.

The act of smelling something, anything, is remarkably like the act of thinking. Immediately at the moment of perception, you can feel the mind going to work, sending the odor around from place to place, setting off complex repertories through the brain, polling one center after another for signs of recognition, for old memories and old connection.

The first drizzling shower is born...
[Then] the flood comes down,
Threatening with deluge this devoted town. ...
Now from all parts the swelling kennels flow,
And bear their trophies with them as they go:
Filth of all hues and odors seem to tell
What street they sailed from, by their sight and smell.
They, as each torrent drives with rapid force,
From Smithfield or St. Pulchre’s shape their course,
And in huge confluence joined at Snow Hill ridge,
Fall from the conduit prone to Holborn Bridge.
Sweepings from butchers’ stalls, dung, guts, and blood.
Drowned puppies, stinking sprats, all drenched in mud,
Dead cats, and turnip tops, come tumbling down the flood.

The phosphorous smell which is developed when electricity (to speak the profane language) is passing from the points of a conductor into air, or when lightning happens to fall upon some terrestrial object, or when water is electrolysed, has been engaging my attention the last couple of years, and induced me to make many attempts at clearing up that mysterious phenomenon. Though baffled for a long time, at last, I think, I have succeeded so far as to have got the clue which will lead to the discovery of the true cause of the smell in question.
[His first reference to investigating ozone, for which he is remembered.]

Through seven figures come sensations for a man; there is hearing for sounds, sight for the visible, nostril for smell, tongue for pleasant or unpleasant tastes, mouth for speech, body for touch, passages outwards and inwards for hot or cold breath. Through these come knowledge or lack of it.