Chemistry, on the contrary, is the science which investigates the composition of material substances, the internal changes which they undergo, and the new properties which they acquire by such changes. The operations of chemistry may be described under the heads of Analysis or decomposition, and Synthesis or combination. Natural Philosophy makes us acquainted with the condition and relations of bodies as they spontaneously arise, without any agency of our own. Chemistry teaches us how to alter the natural arrangement of elements to bring about some particular condition that we desire. To accomplish these objects in both of the departments of science to which we refer, we make use of appliances called philosophical and chemical apparatus, the proper use of which it is the office of Natural Philosophy and Chemistry respectively to explain.
All philosophical knowledge proceeds either from observation or experiment, or from both.
By repeated observations, and by calculations based on such observations, we discover certain uniform modes in which the powers of nature act. Thus, it is a general law that all bodies attract each other in proportion to the quantity of matter which they contain. It is a particular law of electricity that similar kinds repel and dissimilar kinds attract each other. The collection, combination, and proper arrangement of such general and particular laws, constitute what is called Science. In general, an art is that which depends on practice or performance, while science is the examination of general laws, or of abstract and speculative principles.