Mr. Faraday on Chemical Manipulation, 2S1 



ment of electrical machines and apparatus is described, and 

 the circumstances necessary to facilitate investigation and 

 insure success are pointed out. To this succeed tlie ma-: 

 nagement and composition of lutes, and a chapter on bending 

 blowing, and cutting glass. 



Cleanliness, order, and regularity are of the utmost import- 

 ance 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 andi 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 cleanli- 

 ness 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 ind.ulged themselves in slovenly habits. Macquer's ob- 

 servations on this subject, as quoted by our author, are so 

 much to the purpose, and so well deserving the serious atten- 

 tion 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 w^ell 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 ob- 

 served. 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 ves- 

 sels employed, the glasses and bottles filled, so accumulate 

 that he cannot any longer distinguish them ; or at least he is 



