THE COLLIERY GUARDIAN. June 20, 1913. 1340 _______________________________________________________________________________________________________________ CONTENTS. PAGE Editorial Articles .*— The Fourth Report of the Explosions in Mines Committee................................. 1341 Indian Coal Output, 1912....................... 1341 Articles :— Development of Coaldust Explosions............ 1327 The Measurement of Air in Mines .............. 1330 The National Physical Laboratory.............. 1335 Labour and Wages............................ 1342 Draft General Regulations..................... 1344 The Concealed Coalfield of Yorkshire and Notting- hamshire................................... 1347 Mining and Other Notes ....................... 1349 Notes from South Wales....................... 1350 Open Contracts ..............................1350 The Freight Market ....................'___ 1352 Abstracts of Patent Specifications Recently Accepted 1354 New Patents Connected with the Coal and Iron Trades..................................... 1358 Government Publications ..................... 1358 Publications Received ........................ 1358 Indian and Colonial Notes ..................... 1339 Continental Mining Notes .................________ 1342 Coal, Iron and Engineering Companies ......... 1352 The Coal and Iron Trades............ 1336—1339,1343 The By-Products Trade ....................... 1343 The London Coal Trade ....................... 1343 The Tin-plate Trade .......................... 1343 Reports of Meetings:— Manchester Geological and Mining Society....... 1332 South Staffordshire and Warwickshire Institute of Mining Engineers .......................... 1333 Mining Institute of Scotland................... 1335 North of England Institute of Mining and Mechanical Engineers ....................... 1341 Letters to the Editor : — Miner s’ Nystagmus—Mining Exhibition ........ 1349 Miscellanea .*— Wrongful Imprisonment in the Mine — New Railway in Notts............................ 1330 Hull Coal Imports Partnerships Dissolved ..... 1339 Grimsby Coal Exports __...................... 1343 The Edward Medal.........................._________ 1352 Hull Coal Exports .....................______ 1358 SUBSCRIPTIONS. ______ The Colliery Guardian is published at 2.30 p.m. on Friday, and includes the latest intelligence. 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Chart of 187 Mechanical Motions with description of each, post free 6d. ASSOCIATION OF PRIVATE OWNERS OF RAILWAY ROLLING STOCK. Formed in 1891 for the Protection of the Rights and Interests of Private Owners. Applications for particulars and terms of membership may be sent to the SECRETARY, Clarence Chambers, Gloucester. The Oldest Diamond Drill Company. Established 1872. "RORING ?ob AJINERALS. SPEED AND CERTAINTY. CYLINDRICAL “CORES.” THE AQUEOUS WORKS AND DIAMOND ROOK-BORING Co. Ltd Guildford St., York Road, Lambeth, London, S.E. Besides numerous other Important Contracts, completed (in 1897) the Deepest Boring In the United Kingdom to 3,500 ft. Great Experience in Boring for WATER. The Cambrian School of Mines, CEMETERY ROAD, PORTH, GLAM. An University Training at Your Own Home. 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