4*'%sf- CORNELL UNIVERSITY LIBRARY £N,GINE£Hlh,u LiDKAhJf. Cornell Onlversily Library TN 948.F3G78 1919 The mmeral industry of^the^Britl^ Cornell University Library The original of tiiis book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924004640276 IMPERIAL MINERAL RESOURCES BUREAU. THE MINERAL INDUSTRY OF THE BRITISH EMPIRE AND FOREIGN COUNTRIES. WAR PERIOD. FELSPAR. (1913-1919.) LONDON: PRINTED AND POBLISHBD BT HIS MAJESTY'S STATIONERY OFFIOE. To be purchased through any Boolsseller or directly from .H M STATIONEBY OFFICE at the following addreaaea : Imperial House, Kinqswat, London, w.oa, and 28 ABINODON STREET, LONDON, S.W.i; J7 I'ETBR STREET. MANCHESTER ; 1. ST ANDREWS CRESCENT, CARDIFF; 23, FORTH STREET. EDINBORQH ; f r irom E. PONSONBY, LTD., 116, QBAFION STBEBT, DOBUN 1920. Price 6d. Net. 9c/r PKEFACE The following digest of statistical and technical information Tslative to the production and consumption of felspar will consti- tute a part of the Annual Volume on the Mineral Eesources of the British Empire and Foreign Countries. In this, the first year of publication, an effort has been made to fill in, as far as possible, the hiatus due to the war in the pub- lications relating to mining and metallurgical statistics. Labour, health, and safety statistics have been omitted owing to the difficulty involved in procuring reliable information for the war period, but in future issues these statistics will be included in respect of each year. Resort will also be had to a much greater extent than at present to graphical representation of statistics of production, consumption, costs and prices. E. A. S. Ebdmayne, Chairman of the Governors. June, 1920. 2, Queen Anne's Gate Buildings, London, S.W.I. CONTENTS. PACB GENERAL 4 WORLD'S PRODUCTION 6 BRITISH EMPIRE: United Kingdom 6 Canada ... ... ... ... ... ... 8 austiiaija ... ... ... ... ... ... ... 11 FOREIGN COUNTRIES : NOKWAY 11 Sweden 12 United States 14 REFERENCES TO TECHNICAL LITERATURE 15 .(287:iM Wt. 6698-40/747 10 m 7/20 H.St. Q. 2 GENBEAL. Felspars are complex silicates of aluminium and other metals. The chief varieties from the commercial standpoint are : — (1) potash felspar, including orthoclase and microcline, containing potash as well as alumina ; (2) albite, containing soda and alumina; (3) soda-lime felspars, notably ohgoclase and labradorite, containing a mixture of soda and hme as well as alumina. The following representative analyses show the composition of these different kinds of felspars : — Orthoclase Albite Oligoclase Labradorite Silica 65-72 68-46 62-30 52-55 Alumina 18-57 19-31 22-00 28-32 Ferric oxide 0-28 004 2-44 Potash 14-02 0-94 0-64 Soda 1-25 11-27 8-20 4-52 Lime 0-34 0-68 4-86 11-61 Magnesia 0-10 — — 0-48 Totals 100-00 100-00 98-34 100-56 Most of the felspar quarried for industrial purposes is orthoclase or microcline occurring as crystalline masses, or in the form of pegmatite veins or dykes. In order that a deposit of felspar may be quarried at a profit, its dimensions should be such that work can be carried out by the simplest quaiTying methods. Unless there are exceptional transport facilities, it is desirable that a deposit should have a thickness of quite 25 feet. Moreover the felspar should be ob- tainable free from such deleterious minerals as mica, particularly biotite-mica, garnet, tourmaline, hornblende, apatite and pyrites. Felspar is utilized chiefly in the manufacture of pottery. Dr. J. W. Mellor • informs the Bureau that " in the manufac- ture of porcelain on the Continent the felspathic flux is intro- duced mainly as a felspar or felspathic sand. The English porcelain has a flux partly felspar and partly bone ash, where the felspar is introduced with Cornish stone. The Continental hard porcelain is very closely related to the English stoneware and other types of vitreous body used in making insulators, chemical plant, etc." Ferruginous impurity is objectionable as it discolours the finished product. Quartz may, as a rule^ be present up to 20 per cent., but some manufacturers of porcelain specify that the quartz shall not exceed 5 per cent. The use of potash felspar in the manufacture of glass and par- ticularly chemical ware is steadily growing, and much of the output from Cornwall is used for this purpose. In addition to its use in the body and glaze of pottery and chinaware, felspar is an important constituent of most enamels used for coating kitchen utensils and other metal wares. It is essential for white enamels that the percentage of iron oxide should be as low as possible, and as a rule not more than 0'5 per cent, of iron is allowed. Iron-enameUed ware is manufactured chiefly in Austria and Germany. A small amount of low-grade felspar is used in the manu- facture of opalescent glass, and the variety usually employed for this purpose is albite (soda felspar). A little pure-white potash felspar is quarried for the manu- facture of artificial teeth, the proportion of felspar used being about 80 per cent., whilst the remainder is quartz with a httle colouring and binding matter. Felspar is used as a flux in the manufacture of emery and carborundum wheels. The mineral must be ground fine enough to pass a 200-mesh or still finer screen. The waste impure felspar obtained during quarrying opera- tions is ground for use as poultry grit and roofing spar ; probably any coarse-grained granitic rock crushed to a 1'2-mesh would be suitable for these purposes. Many efforts have been made to extract potash from orthoclase and micrccline for use as a fertilizer. Theoretically, pure ortho- clase should contain 16'9 per cent. K2O. Usually the amount of potash in high-grade orthoclase or microcline felspar does not exceed 14 per cent. Most of the processes patented for the extraction of potash are based on the calcination of a mixture of the ground felspar and some salt, such as sodium chloride, or an alkali sulphate, whereby the potash in the spar is converted into a soluble salt and can be recovered by leaching. While many of these patents have proved successful on a laboratory scale, the processes have proved too expensive in practice to allow of potash fertilizers being manufactured from commercial felspar. A new process for the extraction of alumina from labradorite has recently been introduced in Norway. In this process the felspar is leached with a 30 per cent, solution of nitric acid whereby the aluminium, calcium, and part of the iron are con- verted into nitrates, the balance of the iron and the whole of the silica remaining undissolved. After removing the iron, the solu- tion is evaporated to dryness, and the residue heated to such a temperature that the aluminium salt only is decomposed. The nitrogen oxides driven off during ignition are collected in the form of nitric acid. It is proposed to use the sodium nitrate and calcium nitrate by-products as fertihzers, and the alumina for the manufacture of aluminium or aluminium salts. The labradorite occurs as large deposits, forming mountain masses in the Sognef- jord and Ekersund districts of South-West Norway! The felspar is of good quality and contains about 30 per cent, of alumina. Felspar is an important constituent of granites and most other igneous rocks, many of which are used extensively for building and constractional purposes. For ornamental and decorativ& work, much of the value of the stone depends upon the colours and arrangement of the felspars. WORLD'S PEODUCTION. Deposits of felspar of sufficient size and purity, and con- veniently situated as regards cheap transport, are not of common occurrence, and are quarried chiefly in Canada, the United States, Norway and Sweden. The " China stone " or " Cornish stone " produced in the United Kingdom consists essentially of partly decomposed felspar. The United States of America, which has long been the world's^ chief producer of felspar, consumes the whole of its own output in addition to the greater part of the high-grade felspar pro- duced in Cana-da. A large part of the Swedish and Norwegian production is exported to European countries. During the period under review the world's annual production of felspar, including China stone, has never much exceeded •250,000 tons. World's Production of Felspar. {In Metric Tons.*) 1913. 1914. 1915. 1916. 1917. 1918. 1919. United Kingdomf ... 67,714 61,694 40,970 37,473 33,708 37,603 48,651 Canada 15,236 16,388 13,211 17,684 17,661 17,044 Australia 47 Germany (Bavaria) ... — 3,105 1,970 2,650 2,530 Italy — 700 700 900 1,292 1,517 Norway (exports) ... 40,842 27,967 12,607 12,811 4,435 Sweden 37,878 20,818 12.105 12,724 18,533 17,850 United States 109,760 1122,885 95,388 120,400 128,788 89,670 * The metric, long, and gHort tons referred to in this publication are equi- valent to 2204, 2240 and 2000 lb. respectively, t Including China stone. BEITISH EMPIRE. United Kingdom. The bulk of the felspar flux used in the Enghsh potteriea is obtained from " Cornish stone " or " China stone," a peculiar local variety of granite found in the St. Stephen district near St. Austell in Cornwall. Cornish stone may for convenience be considered a natural mixture of felspar and quartz, with kaolin, fluorspar, white mica and topaz as accessory minerals. Frequently China stone and China clay occur in the same quarry, and are both worked. An important feature in Cornish stone is the presence of albite or albite-oligoclase, often fresh and unaltered, in addition to orthoclase. There are several quahties of China stone on the market, namely, hard purple stone, mild purple, dry white, and liuff stone. The differences are due to the varying degrees of alteration ; the soft varieties show a greater degree of krtolinization. Typical analyses of hard purple, dry white, and butt' stones are as follows : — * Silica Alumina Ferric oxide... Manganous oxide Lime ... Magnesia Potash Soda Water... Phosphorus Pentoxide Pluorine Chlorine Titanium dioxide ... Lithia... Per cent. Per cent- Per cent. 72-28 73-18 73-96 14-90 16-13 15-90 0-50 0-52 1-40 0-01 0-02 1-66 0-61 1-89 0-15 0-14 0-32 5-25 4-41 4-34 3-01 2-18 0-45 0-81 2-01 1-11 0-53 0-45 0-88 0-23 0-02 — 0-05 0-06 0-02 0-02 100-07 99-96 99-37 The proportion of kaolin, felspar and quartz that would go to make up a typical sample of hard purple stone or buff stone would be : — Kaolin. Felspar. (^)nartz Purple Stone 67 77-2 16-1 Buff Stone 146 55-5 309 A small quantity of decomposed granite is quarried in the island of Jersey and used for the same purposes as Cornish stone. According to reports which have been received by the Bureau from Prof. Granville A. J. Cole and Prof. P. G. H. Boswell, potash felspar has been quarried during the period under review at Tresayes near Roche, at Kernick near Trevisco, at Trelavour Downs near St. Dennis in Cornwall, and at Castle- caldwell, Co. Fermanagh. Ireland. Felspar appears not to have been raised elsewhere in Ireland in the period 1913-1919, but many occurrences were investigated in several counties. As a result of these investigations it would seem that the felspar-quartz dykes on the south shore of the Gweebarra Estuary in Co. Donegal, the peninsula north of • Handbook to the collection of Kaolin &c. in the Museum of Practical Geology by J. Allen Howe. Analysis of " dry white " by Dr. J. W. Mellor (Trans. Ceram. Soc, 1913, 12, 151). Portnafrancagh in Co. Mayo, the coast one mile west of Great Newton Head in Co. Waterford, and Castletimon Hill in Co. Wicklow would justify further investigation. Output of China stone and Felspar in the United Kingdom* {In long tons.) 1913. 1914. 1915. 1916. 1917. 1918. 1919. China stone — Cornwall 66,626 59,752 37,112 36,121 32,196 34,577 43,043 Felspar — Cornwall Argyll ... Kincardine — 950 3,200 750 970 1,986 136 300 3,021 344 1,330 Total — 950 3,200 750 970 2,422 4,695t Canada4 Practically the whole of the Canadian production of felspar is ■obtained from quarries and open workings situated in the Verona ■district near the town of Kingston on the northern shore of Lake Ontario. Felspar occurs abundantly in aplite and pegmatite dykes throughout the whole of the provinces of Ontario and Quebec and northward through Manitoba into the North- West Territories. These are mostly, however, either small or too remote .to allow •of economic working at present. There are no grinding mills in Canada capable of preparing any considerable quantity of felspar. The whole of the output of high-grade felspar from the quarries is shipped to Ohio and New Jersey, where it is ground and used for the manufacture of pottery and enamelled ware. There is a small grinding plant established at Parham, but it is not equipped with the proper machinery for producing a high-class product. The mill works • Figures supplied to the Bureau by the Chief Inspector of Mines, Home Office. f In addition to this quantity, 131 tons of Felspar were obtained from a mine in Co. Fermanagh, thus making a total output of 4,826 long tons of Felspar proper for the United Kingdom in the year 1919. X "Felspar in Canada" by H. S. de Schmid, No. 401, Mines Branch, Dept. of Mines, Canada, 1916. Annual Reports on Mineral Production in Canada, Dept. of Mines. Annual Reports of the Ontario Bureau of Mines., Annual Reports on mining operations in Quebec. 9 on low-grade felspar, and the output consists wholly of grit used chiefly for roofing purposes. In the Verona district, the felspar quarried is mainly a high grade microcline, occurring in aplite dykes traversing pre- •Cambrian gneisses and crystalline limestones. The felspar is mixed with quartz, and the latter usually occurs in compact masses which are left standing until quarrying operations have removed the felspar, when they are broken down and shipped to the electro-metal works at Welland, Ontario, for the manufacture of ferro-silicon. Deleterious minerals such as tourmaline, pjrites, mica, and hornblende occur in the dykes in varying quantities, but large masses of pure felspar that need very little cobbing or sorting can be obtained. Only the purest mineral suitable for pottery purposes is shipped, and the inferior grades are sent to the waste dump. The following analyses show the compositions of Quebec and Ontario felspars : — Microcline from Villeneuve mine, Quebec. Amazonite Albite ( Peris terite) Microcline from from Leduc from Richardson mine, Quebec. Villeneuve mine, Quebec. mine, Bedford, Ontario. Per cent. Per cent. Per cent. Per cent. Silica 64-54 64-42 65-65 64 44 Alumina 18-81 18-26 21-65 17 63 Ferric oxide 0-08 0-05 0-46 74 Ferrous oxide 0-06 0-03 0-03 03 Magnesia ... 0-02 0-01 0-18 02 Lime 0-57 0-18 1-20 40 Soda 2-68 3-07 9-87 3 31 Potash 13-67 14-16 1-08 13 39 Water 0-10 0-10 0-08 0-12 Titanium Trace Trace Trace Trace dioxide Manganons Trace Trace Trace Trace oxide Strontia Nil Nil Nil Nil Baryta Trace Trace Trace 0-02 Carbon Nil Nil Nil Nil dioxide 1 Owing to the low price obtained for high-class felspar and the longer freight haul, the Quebec quarries have not been able to compete with those of Ontario in American markets. The Quebec felspar is similar to that of Ontario and occurs in the same geological formations. The Villeneuve properties, situated 20 miles north of Buckingham, the nearest shipping port, are operated on a mica pegmatite dyke about 150 feet wide, cutting across garnetiferous gneiss. Mining operations are carried out by open cut and drifting into the hill. The deposits are quarried for mica, the felspars microcline and albite being obtained as bv-products. Both felspars are white and suitable for the manu- facture of high-class china ware. The microcHne can be obtained 10 in a remarkably pure condition. A few tons of this mineral are quarried annually and used in the manufacture of artificial teeth. Prior to the war, the market value of Canadian potash felspar for pottery purposes did not exceed about £1 per ton delivered at the mill, whereas the market value of " dental Spar," as the pure-white microcline is called, was as high as £4 per ton. Other forms of felspar obtainable in this district are amazonstone, a greenish variety of microcline ; and peristerite, a highly iridescent variety of albite. Both these minerals are used in the jewellery and ornamental trades. Pine specimens of labradorite, a lime-soda felspar, are found near Nain on the Labrador coast. The mineral is used as an ornamental stone on account of its wonderful play of colours, and considerable quantities are collected and shipped for the manufacture of buttons, sleeve-links, scarf-pins, etc. Production of Felspar in Canada. Quantity (short tons). Year. Quebec. Ontario. Total. 1913 16,790 1914 — — 18,060 1915 572 13,987 14,559 1916 4,610 14,878 19,488 1917 1,188 18,274 19,462 1918 191 18,591 18,782 1919 Value ($). 1913 60,795 1914 — — 70,824 1915 2,005 55,796 57,801 1916 18,075 53,332 71,407 1917 8,204 81,622 89,826 1918 4,279 108,449 112,728 1919 Exports of Felspar from Canada. Quantity Value Year. (short tons). ($). 1913 . 15,966 62,767 1914 . 18,072 74,100 1915 . » # 1916 . * * 1917 . 69,195 1918 . 101,187 1919 * Not separately stated. 11 Australia.* Affr S(ju(h Wales. — The only recorded production of felspar in New youth Wales during the period under review was a small shipment in the year 1917 of 21 tons of felspar from Hartley ^ ale and 25 tons raised from the Valla property, Nambucca Heads. South Australia. — ^In the hundred of Dudley, Kangaroo Island, South Australia, felspar and China stone have been mined inter- mittently for many years. During the period under review output was restricted to a few parcels of China stone and felspar shipped from time to time. The felspar and China stone occur in a coarsely crystalline granite or pegmatite dyke that traverses altered sedimentary rocks. As far as is at present known the dyke has a length of over 1,000 feet and a width of more than 100 feet. Within the dyke the felspar occurs abundantly, and cubes of this mineral over a foot in size can often be seen. Generally the felspar and quartz are intergrown forming a coarsely crystalline graphic granite. It has been estimated that from one-third to one-half of the dyke consists of felspar and China stone separable by hand-picking. The following analyses are representative of the material available in the hundred of Dudley Silica Alumina Ferric oxide Magnesia Lime Soda Potash . . . Water Per cent. Per cent. 70-20 6610 18-90 20-28 1-02 0-84 Nil. Nil. 008 0-1 -i 2-58 ■2-58 5-74 8-76 0-67 0-50 FOEEIGN COUNTRIES. Norway. Prior to the war Norway produced about 40,000 tons of felspar rock annually. The mineral quarried is a very pure potash felspar, occurring in large irregular masses and pegmatite veins traversing gneiss. The quarries are situated near Hundholm, Bergen, Stavanger, Kristiansand, Narvik, Bodo, and in many other localities, notably near Mosken in the Lofoten Islands. Practically the whole of the felspar quarried in Norway is exported, principally to Germany, Belgiimi, Great Britain, and Russia. Most of the felspar used in the Royal Porcelain Works, Copenhagen, is obtained from the Naresto quarry, between Tvedestrand and Arendal. • .Annual Report Dept. Mines, N.S.W., 1917. Rev. Min. Oper. in S. Australia, January to June, 1917 : No. 26. 12 Sunstone or aventurine spar is quarried to a small extent at Tvedestrand, and is used for the manufacture of fancy buttons, sleeve-links and- other such articles. Mention may be made of the beautiful Norwegian syenite known as laurvigite, which is used largely in Great Britain for decorative building purposes, on account of the play of colours it shows on polished surfaces. The rock is quarried from the Laurvig and Frederiksvaem districts, and consists chiefly of felspar. The following is an analysis of Norwegian felspar reported by H. Seger (Gesammelte Schriften, Berlin, 415, 1896) :— Per cent. 6498 Silica Alumina Ferric oxide .. Lime Magnesia Potash ... Soda Loss on ignition 1918 0-33 Trace 0-25 12-79 2-32 0-48 Exports of Felspar from Norway* Quantity Year. (metric tons). 1913 40,842 1914 1915 1916 1917 1918 ]919 27,967 12,607 12,811 4,485 Value (£). 34,140 25,054 12s097 14,892 10,108 Sweden. Sweden possesses many important deposits of felspar rock. Formerly, the felspar was obtained chiefly from Ytterby pegmatite on the Island of Eesar, but this district does not at present produce any important quantity. The bulk of the Swedish output of felspar is obtained from the quarries at Kolsva in the Vestmanland district, Margretelund in the Stock- holm district, and Drom in Ostergotland. In the Island of Quest on the south-west coast there are many large outcrops, very few of which are worked., Other important deposits are worked in the coast section around Lulea and Eanea in Norbotten. Very little of the felspar produced is consumed in domestic potteries and the greater bulk of the output is shipped to Euro- pean porcelain works in crude lump form. There are only two felspar grinding mills in Sweden, one at Klinktjarn, near Kolsva, * Norges Bergverksdrift. Value converted to £1 sterling at the rate of 18-6 Kroner = £1. 13 operating on a low-grade graphic granite containing about 20 per cent, of quartz, and the other at Baldersnas, near Stockhohn. The follow ing analyses of Swedish felspar are quoted by W J . Furnival (T.eadless decorative tiles, etc. ; Stone, 331, 1904) :— Per cent. Per cent'. Silica 6440 65-30 Alumina . . . 1930 1971 Ferric oxide 030 0-64 Lime 0-40 0-68 Magnesia — 0-18 Potash 12-55 8-81 Soda 2-58 7-32 Production of Felspar in Sweden.* Quantity Value Year. (metric tons). £ 1913 37,878 18.312 1914 20,818 10,730 1915 12,105 6,705 1916 12,724 6,747 ]917 18,533 14,213 1918 17,850 15,558 1919 Imports of Felspar to Sweden.} Quantity Value Year. (metric tons). i' 1913 172 379 1914 25 49 1916 32 209 1916 200 392 .1917 191 539 1918 96 812 1919 Exports of Felspar from Sweden.* Quantity Value Year. (metric tons). £ 1913 38,072 41,837 1914 16,845 15,991 1915 10' 703 10,016 1916 13,8-20 12,774 1917 ... 14,112 15,003 1918 15,854 16,266 1919 Value con- • Bergshantering Berattelsee av Kommerskollegium (Annual), verted to £ sterling at the rate of lR-2 Kroner = £1. f Statistisk Arabok for Sverige. Value converted to £ sterling at the rate of 18-2 Kroner = £1. 14 United States of America.* The United States is the greatest producer of felspar in the world. Prior to the war, there were about 50 quarries operating in the States of Maryland, New York, Virginia, North Carolina, Maine, and Connecticut. There are few, if any, large producers of high- grade felspar. Most of the larger properties operate on low-grade material. Felspar deposits in the United States are usually opened up to obtain the pure mineral known as dental spar, and when no more of this material can be obtained, the high-grade felspar is quarried and sold to operators of low-grade material. In course of time, with the exhaustion of this better-class material, the quarry either closes down or buys high-grade material from porae newly opened quarry to mix with its low-grade product. The felspar quarried in the United States is chiefly the potash variety, but most quarries yield some soda felspar. Much of the material quarried by the larger producers is a coarse-grained granite carrying a nearly constant proportion of quartz and felspar. A typical quarry yields a product containing about 70 to 80 per cent, of felspar, the remainder consisting of quartz. The great bulk of the crude and ground high-grade felspar is sent to the chief pottery centres at Trenton, New Jersey; and East Liverpool, Ohio. Other important potteries are situated at Philadelphia and Toughkenamon , Pennsylvania ; Syracuse, New York ; Coshocton, Ohio ; and Chester and Wheeling, A^irginia. In addition to the domestic production of felspar, the United States imports almost the whole of the Canadian production and a considerable tonnage of Cornish stone from Great Britain. Very little Norwegian or Swedish felspar is imported. Prior to the war, the cost of mining felspar at most American quarries would run from $2 to |2.50 per long ton for high-grade minerals. As the selling price for crude felspar at that date was not more than $3'31 per ton and $8'31 for ground material, it was essential that transportation should be kept as low as possible. A haul of more than two or three miles to the railway would render most of the low-grade deposits unprofitable. Felspar Sold by Producers in the United States. Crude. Ground. Total. Year. Quantity Value. Quantity Value. Quantity Value (t) (short tons). ($) (short tons). (*) (short tons). (1) 1913 45,391 148,549 75,564 628,002 120,955 776,551 1914 85,905 263,476 49,514 366,397 135,419 629,873 1915 — — — — 105,118 489,223 1916 — — — — 132,681 702,278 1917 — — — — 141,924 728,838 1918 — — — — 98,816 674,745 1919 Annual Reports on Mineral Resources of the United States, (t) Value as sold (crude and ground). 15 REFERENCES TO TECHNICAL LITERATURE. Memoirs of the Geological Survey ; Special reports on the mineral resources of Great Britain 1917, 5, 1-14. A neglected cliemical reaction and an available source of potash, by E. A. Ashcroft; Bull. Inst. Mm. Met. No. 159, 1917, 20 pp. Potash from felspar, by D. J. Benham ; Met. Chem. Eng., 1917, 16, 704-705. Abstr. Journ. Soc. Chem. Ind., 1917, 36, 960. British supplies of potash-felspar, considered from the glass-making point of view, by P. G. H. Boswell ; Trans. Soc. Glass Technology, 1918, 2, 35-71. A memoir on British resources of sands and rocks used in glass-making, with Dotes on certain crushed rocks and refractory materials, by P. G. H. Boswell ; 2nd edn. London: Longmans, Green and Co., 1918. Possible sources of potash, by C. G. Cresswell; Journ. Soc. Chem. Ind., 1915, 34, 387-393. Felspar as a possible source of American potash, by A. S. Cushman. and G. W. Coggeshall; Met. Chem. Eng., 1915, 12, 99-104. Abstr. Journ. Soc. Chem. Ind., 1915, 34, 79. Recovery of potash and aluminium salts from mineral silicates, by J. C. W. Frazer, W. W. Holland, and E. Miller; Journ. Ind. Eng. Chem., 1917, 9, 935. Abstr. Trans. Ceramic Soc, 1918-19, 18, A. 36, and Journ. Soc. Chem. Ind., 1917, 36, 1234. Report on the non-metallic minerals used in Canadian manufacturing industries, by H. Frechette; Mines Branch, Canada, Publication No. 305, 1914, 199 pp. (Felspar, 37-40). Felspar and mica deposits of Georgia, by S. L. Galpin,; Georgia Geol. ■ Surv. Bull. No. 30, 1915. Felspar in New South Wales, by L. F. Harper; N.S.W. Geol. Surv. Min. Res. No. 26, 1917, 17 pp. Potash felspar in Norway, by A. Holter; Norwegian Trade Rev., 1919, 4, 63-66. Abstr. Journ.' Soc. Chem. Ind., 1920, 39, 133 11. Softening points of potash-felspar-steatite mixtures, by W. S. Howatt; Trans. Amer. Ceramic Soc, 1916, 18, 488-491. Abstr. Journ. Soc. Chem. Ind., 1917, 36, 714. Chemisch-technische Verwertung des Kalifeldspats, von L. Jesser; Haudbuch der Mineralchemie, C. Doelter; 1917, 2, 567-579. Jungner's method of potash extraction from felspar, etc., in cemont burn- ilig; Chemiker-Zeitung, 1915, 39, Rept. 63. Abstr. Journ. Soc Chem. Ind., 1915, 34, 421. Felspar, by F. J. Katz; U.S. Geol. Surv. Min. Res. U.S., Annual. Fusion study of the mineral sy.stems felspar-calcite and felspar-magnesite, bv F. A. Kirkpatrick; Trans. Amer. Ceramic Soc, 1916, 18, 575-618. Abstr. Journ. Soc. Chem. Ind., 1917, 36, 714. Mineralogical exploration of East Tempieton district, Quebec, by A. Ledoux; Summ. Rept. Geol. Surv. Canada, for 1915, 162-168 (Fel- spar, 165-166). Some notes on hard or felspathic porcelain, by J. W. Mellor; Trans. English Ceramic Soc, 1914-15, 14, 176-192. A commercial method of testing felspar, by J. Minneman; Trans. Amer. Ceramic Soc, 1913, 15, 101-111.' Abstr. Trans. English Ceramic Soc, 1914-15, 14, A. 3. Die Aufschliessung von Felspat zum Zwecke der technischen Kaligeninnung, von. B. Neumann and F. Draisbach, Zeit. f. angew. Chemie, 1916, 29, 313-319, 326-331. Abstr. Journ. Soc. Chem. Ind., 1916. 35, 1012. 16 Feldspar in Canada, by H. S. de Schmid; Mines Branch, Canada, Publi- cation No. 401, 1916, 125 pp. Production and fertiliser value of citric-soluble phosphoric acid and potash (from felspar, etc.), by W. H. Waggaman; U.S. Dept. Agri- culture, Bureau of Soils Bull. No. 143, 1914, 12 pp. Abstr. Journ. Soc. Chem. Ind., 1914^ 33, 293. Felspar, by A. S. Watts and J. T. Singewald; Min. Ind., Annual. Felspars of New England and Northern Appalachian States, by A. S. Watts; U.S. Bur. Min. Bull. No. 92, 1916, 181 pp. Felspar; a deformation study of some felspar and felspar-quartz mixtures, by A. S. Watts; Trans. Amer. Ceramic Soc, 1913, 15, 144^166. Mining and treatment of felspar and kaolin in the Southern Appalachian region, by A. S. Watts; U.S. Bur. Min. Bull. No. 53, 1913, 170 pp. Use of mixed potash-soda felspars in porcelain, by A. S. Watts; Trans. Amer. Ceramic Soc, 1914, 16, 212-215. Abstr. Journ. Soc. Chem. Ind., 1914, 33, 1049. Trans. Ceramic Soc, 1916-17, 16, A. 3. Felspar supply of the United States, by A. S. Watts; Trans. Amer. Ceramic Soc, 1914, 16, 80-95. Abstr. Journ. Soc. Chem. Ind., 1914, 33, 1049. Deformation study of kaolin-felspar mixtures, by H. Wilson; Trans. Amer. Ceramic Soc, 1913, 15, 217-232. Potash in felspar; Rept. Min. Oper. Quebec for 1914, 82-88. Felspar; Rept. Min. Oper. Quebec for 1916, 53-57. Felspar mining in Ontario; Can. Min. Journ., 1917, 38, 8.