The mode of determining the value of alcaline substances, or “alcalimetry,” is described at length in this section. Our readers, however, will here recollect that there is an error respecting the specific gravity of the acid, which Mr. Faraday has corrected at page 221 of the present volume of this Journal. The thirteenth section is allotted to crucible operations, and the fourteenth to furnace tube operations. They are full of minute and admirable instructions, evidently deduced from long experience, and detailed with the same precision and clearness which we have already eulogised. The fifteenth section, which occupies nearly a hundred pages, relates to “pneumatic manipulation, or management of gases.” Every paragraph of the instructions here given will be found to contain something of importance to the student; it is, indeed, a valuable essay upon a difficult and nice department of chemical research. Under the head “Tube Chemistry,” in the sixteenth section, a variety of means are pointed out, of working with and employing glass-tubes, as substitutes for more expensive and formal apparatus. Indeed, the young chemist cannot do better than practise the art of bending, drawing out, and sealing tubes, as here directed, (and in the nineteenth section,) by which he will soon gain the requisite dexterity in forming them into test tubes, retorts, and so on, and be enabled to furnish his laboratory with a quantity of very useful vessels and apparatus, at a very moderate expense. The application of electricity to chemical purposes forms the subject of the seventeenth section, in which the [p281] management of electrical machines and apparatus is described, and the circumstances necessary to facilitate investigation and insure success are pointed out. To this succeed the management and composition of lutes, and a chapter on bending blowing, and cutting glass.