“The lectures profess to be exhaustive and thus present all that Davy had been able to collect on the subject of the relations of chemistry to agriculture during a period of at least 10 years. He appears to have made a careful study of the problems of agriculture for many years, and to be acquainted with English practice, and English experiments. There is but little reference to foreign practice, or foreign opinion, save where the work done has been purely chemical, as _e.g._ that of Gay Lussac, or Vauquelin. He approaches his subject in a thoroughly scientific manner, taking an independent view of each question, bringing all the knowledge at his disposal to bear upon it, and not hesitating to come to conclusions different from those usually received. The _great step_ taken in these lectures is the assertion that Agriculture must look to Natural Science, and especially to Chemistry, for the explanation of its problems and the improvement of its practice. Davy seems to have been the first, at least in this country, who boldly claimed for ‘Agricultural Chemistry’ the position of a distinct branch of science. He was probably the earliest example of a first-class chemist, who seriously and continuously devoted his best attention to the subject of agriculture. “The lectures, looked at from a modern standpoint, are of unequal value. The method of food-analysis is very poor, and it is somewhat surprising that the accurate mode of determining nitrogen employed by Gay Lussac is not made use of in Davy’s analyses. Nevertheless he manages to ascertain that spring sown wheat is richer in gluten than autumn sown, and the wheat of hot countries richer than the wheat of temperate regions, statements which are quite correct. “Lecture VI. is decidedly poor. Davy believes that plants feed on carbonaceous matter by their roots, and this mistaken theory leads him to assign an undue value to organic substances as manures. It seems curious nowadays to find the whole subject of manures treated with hardly any reference to their contents in nitrogen, phosphoric acid, or potash. “Lecture IV. is one of his best lectures, full of keen observation and suggestive experiment. “The references to his own agricultural experiments are very numerous; he seems to have made experiments on every subject of inquiry that came before him. There is however no attempt at an extended and thorough investigation of any subject, and for want of this the truth is sometimes missed. Thus in his trials of various ammonium salts as manures he finds the carbonate to be effective, the chloride to be of little value, and the sulphate of no good at all, whereas the last-named salt is now generally chosen as a manure.