AN ENUMERATION OF THE SCIENCES 29

practical results in the microscope, telescope, spectroscope,

and other instruments constructed in accordance with its

laws.

Acoustics is the science which concerns itself with sound,

its propagation, reflexion, and diffusion through aerial waves

in all directions, with the laws of musical sounds or notes,

the nature of timbre, and various conditions presented by

different musical instruments.

The science of Electricity is one the amazing consequences

of which are familiar to everyone, so that we need but

mention its name together with that of Magnetism, so

intimately connected with it, and pass on to the science

of Chemistry, which has a distinct, though very indirect,

connexion with the subject of this work.

All the sciences which treat of solids, fluids, and the

already-mentioned physical energies, plainly exhibit what

are commonly termed the laws which govern nature,

but had better be called the definite tendencies which are

innate in the substances which compose the universe. Yet

Chemistry is, above all, distinguished by the clear and

unanswerable manner in which it demonstrates that these

tendencies act in clearly defined directions, and build up

by a selective agency certain bodies and none others.

Such is the case whatever may be the reduction in number

of what are at present considered elementary substances,

even if we should ultimately become convinced that

the material world is composed only of inconceivably

numerous combinations of particles of one elementary

substance. Processes of analysis and synthesis demonstrate

the definite proportions in which alone different (as yet

seemingly distinct) substances can unite and transform them-

selves into others not less well defined ; while Crystallography

reveals the extraordinarily definite shapes into which alone

definite substances can crystallize, two such substances of

practical results in the microscope, telescope, spectroscope,

and other instruments constructed in accordance with its

laws.

Acoustics is the science which concerns itself with sound,

its propagation, reflexion, and diffusion through aerial waves

in all directions, with the laws of musical sounds or notes,

the nature of timbre, and various conditions presented by

different musical instruments.

The science of Electricity is one the amazing consequences

of which are familiar to everyone, so that we need but

mention its name together with that of Magnetism, so

intimately connected with it, and pass on to the science

of Chemistry, which has a distinct, though very indirect,

connexion with the subject of this work.

All the sciences which treat of solids, fluids, and the

already-mentioned physical energies, plainly exhibit what

are commonly termed the laws which govern nature,

but had better be called the definite tendencies which are

innate in the substances which compose the universe. Yet

Chemistry is, above all, distinguished by the clear and

unanswerable manner in which it demonstrates that these

tendencies act in clearly defined directions, and build up

by a selective agency certain bodies and none others.

Such is the case whatever may be the reduction in number

of what are at present considered elementary substances,

even if we should ultimately become convinced that

the material world is composed only of inconceivably

numerous combinations of particles of one elementary

substance. Processes of analysis and synthesis demonstrate

the definite proportions in which alone different (as yet

seemingly distinct) substances can unite and transform them-

selves into others not less well defined ; while Crystallography

reveals the extraordinarily definite shapes into which alone

definite substances can crystallize, two such substances of