The history of each science, be it mathematics or astronomy, botany, zoology or geology, shows us that it is not enough to have the intelligent observer, or even the interpretative thinker with his personally expressed doctrine. This must be clearly crystallised into a definite statement, method, proposition, "law" or theory, stated in colourless impersonal form before it is capable of acceptance and incorporation into the general body of science. But while astronomer and geologist and naturalist can and do describe both the observational results and their general conceptions in literary form, requiring from the ordinary reader but the patience to master a few unfamiliar terms and ideas, they also carry on their work by help of definite and orderly technical methods, descriptive and comparative, analytic and synthetic. These, as far as possible, have to be crystallised beyond their mere verbal statement into formulae, into tabular and graphic presentments, and thus not only acquire greater clearness of statement, but become more and more active agencies of inquiry--in fact, become literal _thinking-machines_. But while the mathematician has his notations and his calculus, the geographer and geologist their maps, reliefs and sections, the naturalist his orderly classificatory methods, it has been the misfortune and delay of political economy, and no small cause of that "notorious discord and sterility" with which Comte reproached it, that [Page: 67] its cultivators have so commonly sought to dispense with the employment of any definite scientific notations; while even its avowed statisticians, in this country especially, have long resisted the consistent use of graphic methods. I submit, therefore, for discussion, as even more urgent and pressing than that of the general and abstract methodology of the social sciences, the problem of elaborating a concrete descriptive method readily applicable to the study and comparison of human societies, to cities therefore especially. To do justice to this subject, not only the descriptive labours of anthropologists, but much of the literature of sociology would have to be gone through from the "Tableau Economique" of the Physiocratic School to the "Sociological Tables" of Mr. Spencer, and still more fruitfully to more recent writers. Among these, besides here recognising specially the work of Mr. Booth and its stimulus to younger investigators, I would acknowledge the helpful and suggestive impulse from the group of social geographers which has arisen from the initiative of Le Play[7], and whose classification, especially in its later forms[8], cannot but be of interest and value to everyone whose thought on social questions is not afloat upon the ocean of the abstract without chart or bearings. [7] La Nomenclature Sociale (Extrait de La Revue, "La Science Sociale," Dec. 1886) Paris, Firmin-Diact, 1887.