Cleanliness, order, and regularity are of the utmost importance in the laboratory; and though the appearance of the chemist himself is often such that he appears “to doat upon dirt,” the strictest nicety must generally be observed in the state of his utensils and apparatus. These matters must, indeed, generally engage his personal attention; and it is not sufficient that glasses and other vessels be merely washed and wiped in the usual way, but they are generally required to be free from the minutest portions of adhering matter. A section is accordingly appropriated to the subject of cleanliness and cleansing, in which, and in that which follows it, entitled “General Rules for young Experimenters,” much information is conveyed that will prove useful to those who are commencing the practice of experimental inquiries in chemistry, and also to such as, having made some progress, have indulged themselves in slovenly habits. Macquer’s observations on this subject, as quoted by our author, are so much to the purpose, and so well deserving the serious attention of the young chemist, that we shall stand excused for inserting them in this place. He says, “A persuasion must exist that arrangement, order, and cleanliness, are essentially necessary in a chemical laboratory. Every vessel and utensil ought to be well cleansed as often it is used, and put again into its place; labels ought to be attached to all the substances, mixtures, and products of operations which are preserved in bottles or otherwise; these should be examined and cleansed from time to time, and the labels renewed when required. These cares, although they seem to be trifling, are, notwithstanding, the most fatiguing and tedious, but the most important, and often the least observed. When a person is keenly engaged, experiments succeed each other quickly; some seem nearly to decide the matter, and others suggest new ideas; he cannot but proceed to them immediately, and he is led from one to another; he thinks he shall easily know again the products of his first experiments, and therefore he does not take time to put them in order; he prosecutes with eagerness the experiments which he has last thought of, and in the mean time the vessels employed, the glasses and bottles filled, so accumulate that he cannot any longer distinguish them; or at least he is [p282] uncertain concerning many of his former products. This evil is increased, if a new series of operations succeed, and occupy all the laboratory; or if he be obliged to quit the place for some time, every thing then goes into confusion. Hence it frequently happens that he loses the fruits of much labour, and that he must throw away almost all the products of his experiments.