literally limited according to Webster's definitions and modified by our own restrictions; proved oil land is certain for all practical purposes; probable oil land begins with that on which the chances are greater for commercial production than against, and possible oil land ranges from that which has practically no chance to that with an even chance of producing oil in commercial quantities. The essence of the definition is the distance of the land from production and the fact that the only geoloigc evidence available for consideration is that furnished by surface indications. Synclines in some regions may be rated as possible; "spotted" fields will contain much possible land; in fact, any area, where a majority of chances are against the existence of oil, but where some prospects for oil are found, may be called possible. Possible and probable oil land is further distinguished from proved land by the lack of a basis for estimating their future production. In the first place, there is no practical certainty that lands in either of these classes will produce oil, whereas, there is a practical certainty that proved land will produce oil. Furthermore, a basis of estimating how much it will produce consists in the records of nearby wells. No such basis exists for the estimation of the future production of possible oil land; assumptions only can be made on the basis of the land's becoming productive. Commercially Non-productive Oil Land.-Commercially nonproductive oil land is that on which commercially productive wells can not be drilled at present. In many fields this definition will not be used extensively, but in such fields as those in California, there are many areas where the presence of oil is practically proved, but the wells are so expensive that they can not at present be drilled with profit. Probable and possible oil land may also be rated as commercially nonproductive, contingent, of course, on the final proof that oil exists there. No land can be placed in this and in any of the other classes at the same time, for if land is proved it will support commercial producers. If the existence of oil is proved but wells can not be drilled with profit, the land, according to our definition, can not be placed in the proved class. The same argument applies to the other two classes, which are differentiated by their prospects of obtaining oil in commercial quantities. If the existence of oil is probable under a tract of land, and the sand is beyond the reach of the drill, the land must be commercially non-productive. CONCLUSION. Land can be classified into the proposed classes usually without great difficulty, and if the boundary lines of different areas are made according to legal subdivisions, the amount of acreage can be readily computed. Exceptions undoubtedly will be found, and some cases will be very difficult to settle. For instance, in some places the existence of productive zones or sands below a producing sand may be probable or possible. Different areas may be placed in all four different classes, for some of it may be proved and some may be probable, possible, or commercially non-productive. Each sand, therefore, may require a different classification; they must be considered as separate tracts or fields. The drilling of a gas well on an anticline or dome may cause a difference of opinion as to the oil prospects of the land, and an analysis of the gas may lead one to believe in the existence of oil on the flanks of the fold, whereas, another, without the analysis, would claim that no oil existed in the reservoir. Most of these cases, however, may be settled by a close study of conditions, based on a comprehensive knowledge of oil accumulation, origin and movement. Land may change rapidly from one class to another. The drilling of one well may prove an extensive area that previously was probable or possible, or it may serve to place commercially non-productive oil land in the proved class. Water troubles may develop, suddenly causing proved areas to lose much of their value and place them in the probable class, or the price of oil may increase to such an extent that wells may be drilled with profit on land where the existence of oil was previously certain, but which was unprofitable to drill. Known oil-bearing sands, lying below the depth of the drill, and thus commercially non-productive, with improved drilling methods, may later be drilled with profit. In fact, any development that brings forth more evidence may change the classification greatly. 523 WELLS FARGO BLDG., SAN FRANCISCO, Cal. THE DEVELOPMENT OF IRON ORE IN GREAT BRITAIN DURING THE WAR. F. H. HATCH. INTRODUCTION. During 1917 and 1918 the writer was engaged officially with others in the iron and steel department of the Ministry of Munitions on a study of the iron-ore deposits of the United Kingdom. The progress of the war had, by the end of 1916, produced a serious position in the iron and steel trade: the working stocks of hematite ore were much depleted and at some iron work had practically disappeared, with the result that furnaces were entirely dependent on the arrival of shipments, and several had to be put out of blast. To meet this position it was decided to increase the production of iron-ore in the United Kingdom. Sir John Hunter, director of iron and steel production, acting under the instructions of the Minister of Munitions, obtained the services of a number of mining engineers and of experts versed in the different branches of the iron and steel industry with whom he formed sections of the iron and steel department to deal respectively with the mining and quarrying of iron-ore and limestone, with the supply of fuel, refractory materials and labor, and with the reorganization of both blast-furnaces and steel furnaces. In the early part of 1917, a comprehensive survey of the ironore resources of the United Kingdom was undertaken and I propose in this article to show how the home production of iron-ore was by the end of the year 1917 increased by a million and a half tons, and during the first part of 1918 by an amount equivalent to 23 million tons per annum. History. The first historical reference to Great Britain mentions the export of tin from Cornwall. Also, this country's production and export of copper in the early part of the nineteenth century were the largest in the world; but for its modern industrial preeminence it is indebted to its coal and ironstone and particularly to the fact that these materials are in part so closely associated in nature that for a time the factor of transportation. was practically eliminated. But the gradual exhaustion of the richer blackbands and clay-ironstones of the Carboniferous formation, and the introduction of the acid Bessemer process of steel manufacture, which requires a pure ore free from phosphorus and sulphur, made it necessary to find other sources of iron-ore supply. For many years the United Kingdom has been dependent, for 30 per cent. of the iron-ore used in its blast-furnaces, on foreign countries. Foreign ore plays even a bigger rôle than at first appears, since its average iron content is 50 per cent. as against 30 per cent. for home ores. The importation of hematite, rich in iron and low in phosphorus, from Spain and the Mediterranean, built up the big iron industries now engaged in the manufacture of steel by the acid process in South Wales, on the northwest coast, on the northeast coast, and in Scotland, where the ports of Cardiff, Port Talbot, Whitehaven, Barrow, Middlesbrough, Newcastle and the Clyde, situated in close proximity to an ample supply of labor, enable foreign ore and native coal to be easily assembled and cheaply handled. Cheap water-transport is the basis of this successful importation of foreign ore; but it was found to have its drawbacks when the war broke out; and the scarcity of ship-tonnage raised the cost of imported ore from about 20s. ($4.86) (at which best Bilbao ore ruled in British ports in 1914) to an actual price of over £6 ($29.15) per ton, although, under the cloak of government subsidies, it figured at a lower level. At one period of the war the supply from these sources threatened to be cut off altogether. To meet this situation an increased development of the Jurassic ironstones was decided on. These ironstones, although abundant and cheaply worked, are what the ironmasters term “lean," that is to say they are low in iron, averaging only 28 per cent. of that metal. Moreover, they have a high phosphorus and sulphur-con |