ABSTRACT
Chemistry was nothing but a confused collection of vague notions until the exact determinations of the balance were employed, and the proportions of the substances combining or separating in chemical actions were found to be related by certain simple and very definite laws. To recording instruments, meteorology is also largely indebted for the remarkable progress which it is making, and which will soon place this branch of knowledge in a condition to supply the most striking illustration of the difference between a science founded on accurate measurements and a mass of vague observations. The instrument, as actually constructed, registers also the height of a wet-bulb thermometer, by another wire requiring a lower depression of the lever to bring it into contact with the mercury in a wet-bulb thermometer. The science of gunnery has acquired an exactness unknown before electricity was made to carry messages from the cannon-ball in its swiftest flight, and to write the record of its own course.
