It is this same portability which is constantly increasing the demand for good and rare stamps from collectors. For the majority, almost any form of collecting brings with it a serious problem of space, arrangement, and security. We may display our collection of old English porcelain about the house, and beautify our surroundings, but it is at the cost of no little risk from the philistine fingers of the abigail. We may bring together a great array of ornithological specimens, but the cabinet space taken up by a collection of but moderate proportions is out of all comparison to the compact album, which may contain a large and portable collection of stamps. I would not be understood to even cursorily enter upon comparisons of different hobbies, but it is useful to mention the comparative facility with which transactions in rare stamps can be negotiated to indicate the cumulative effect this convenience must have in the value of old stamps. Another important factor is the comparative standardisation of stamp values. No person of average intelligence need ever be totally in the dark as to the approximate selling value of the majority of old postage-stamps, for in nearly every language, excepting some of the Oriental tongues, there are standard price-lists of the leading dealers which serve as guides to the majority of both buyers and sellers, for these works are accessible both to the dealer and the collector. When we come to consider the supply of old postage-stamps, we cannot but recognise a further important factor in their security as an investment. The majority of the rare, medium and common postage-stamps have been issued with the Government imprimatur; re-issues and reprintings are known, but they are the exception. Generally speaking, a stamp is no sooner obsolete than it commences to soar in the stamp-dealers' price-lists. In the cases of stamps of the larger countries which have had a long period of currency the rise is slow, but the frequency of the occurrence of unusual circumstances which cut short the life of a stamp on the active postal list has introduced a sporting element into even the collecting of current stamps. But it is inevitable that, with the retirement of a postage-stamp from use, there must come sooner or later a stoppage in the supply at the normal rates prevailing during its period of currency. The older stamps, most of the early issues of all countries, have for fifty years past been gradually absorbed in the great collections, some of them extremely limited in their original use, now withdrawn from the market into the stable repositories of national museums, and the supply is the one serious difficulty with which the dealer has to contend. This difficulty has its value to the collector, for to replenish their stocks the dealers have to buy back from the collector, and they compete keenly for the acquisition of collections formed by private individuals, if they contain the right class of stamps.