Ether is a diffusible stimulant, narcotic and antispasmodic. 

What is ether?

Ether is a product obtained by distilling strong alcohol  and sulphuric acid. The product is called sulphuric ether, but it does not contain sulphuric acid, nor has it any sulphur in its composition.

What are the properties of ether?

It is an exceedingly volatile, inflammable  body, producing insensibility when inhaled, and readily dissolving all fatty and oily bodies.

Why will ether remove spots of oil, paint, or grease from garments?

Because it is a solvent  for all greasy, oily matters.

The ether is a hypothetical thing that was invented to explain the phenomena of light. Light is theoretically due to transverse vibrations of the ether. Since the days of Young the conception of the ether has extended, and now light, "radiant heat," and electricity are all treated as phenomena of the ether. Electrical attraction and repulsion are explained by considering them due to local stresses in the ether; magnetic phenomena as due to local whirlpools therein. The ether was originally called the luminiferous ether, but the adjective should now be dropped. Its density is put at 936E-21 that of water, or equal to that of the atmosphere at 210 miles above the earth's surface. Its rigidity is about 1E-9 that of steel (see Powers of Ten); as a whole it is comparable to an all-pervading jelly, with almost perfect elasticity. The most complete vacuum is filled with ether.

All this is a hypothesis, for the ether has never been proved to exist. Whether gravitation will ever be explained by It remains to be seen.

[Transcriber's note: The Michelson-Morley experiment in 1887 (five years before this book) cast serious doubt on the ether. In 1905 Einstein explained electromagnetic phenomenon with photons. In 1963 Edward M. Purcell used special relativity to derive the existence of magnetism and radiation.]