These include the questions of suitability for immigration and colonisation. What is known as commercial geography is one of several special applications of geographical knowledge. From this practical point of view, therefore, the observations collected under other heads in this book will be of service, especially if the requirements of commerce are kept in view at the same time as the _desiderata_ of science. From this standpoint, the sections on Meteorology, Geology, Natural History, and Anthropology should be consulted. Even general geographical and topographical observations will be of practical service—the general lie of the country, its altitudes, and its character at certain altitudes, its mountains, hills, valleys, plains, rivers—if regarded from the special standpoint of habitability and possibilities of development. The suggestions contained in this, as in the other sections of this manual, are meant both for the ordinary explorer or traveller who may have to pass rapidly through a country and for those who may have more opportunity for making leisurely observations. To the former the following brief hints may prove serviceable:— Observe and note— 1. As regards RESOURCES:— The extent or quantity, quality, facilities for raising or collecting, for transport and shipment, etc., of (_a_) The natural products, such as minerals and metals, especially gold, silver, coal, iron, copper, tin, nitre, guano, phosphates, etc.; timber useful for various purposes; vegetable products, useful for food, fibres, dye-stuffs, or medicine—gums, resins, etc.; animal products useful for food, skins, fur, feathers; riverine or lacustrine products, useful for food, oil, or other purposes. (_b_) Substances cultivated for food or for manufacturing purposes. (_c_) Articles manufactured for clothing, for domestic, warlike, or other purposes. (_d_) Native methods of developing resources, of carrying on manufactures, and of transport. (_e_) Practicability of developing the resources of the country by European methods. 2. As to WANTS:— (_a_) What particular things used by the natives could be profitably supplied from the outside? (_b_) What do the natives lack that might be introduced and supplied from the outside? (_c_) In all cases be particular to note favourite materials, shapes, colours, or other peculiarities, as of cloths, implements, ornaments, such as beads, anklets, etc. 3. As to ACCESSIBILITY:— Note the nearest ports and railways; the character and connections of native roads, if any; the navigability of rivers, inlets and lakes for various kinds of craft at various seasons of the year; heights of passes, whether suitable for animals or only for porters, whether blocked at any season of year; routes likely to be suitable for railways.