520 



NAT URL 



[January 7, 19 15 



action is perhaps the most interesting. It is worth 

 while to direct attention to a sentence in the preface 

 by Mr. George Otis Smith : — " It should be em- 

 phasised that the results thus far obtained afford no 

 adequate basis for any method of electric prospecting 

 nor any promise of the development of such a method 

 by connecting the presence of ore deposits with readily 

 or definitely measurable electric activity." Although 

 no very definite results are recorded in this bulletin, 

 it contains much suggestive material, and will probably 

 lead to a fuller investigation of the subject. 



We have also received a series of pamphlets dealing 

 .vith the mineral production of the United States for 

 1913. In order to enable this information to be issued 

 with the least possible delay, each chapter is issued 

 separately as soon as the necessary statistics shall have 

 been prepared, instead of waiting as heretofore until 

 the whole of the statistical information needed for the 

 entire volume was available. This system not only 

 enables the various chapters to be issued more promptly 

 but enables a producer to whom the statistics of one 

 or of a limited number of substances alone are of 

 importance to concentrate his attention on these and to 

 find what he needs in a handy little pamphlet instead 

 of having to deal with a bulky volume. The chapters 

 hitherto published are — 



Part i., "Metals": — (i) Bauxite and aluminium; 

 (2) chromic iron ore ; (3) gold, silver, copper, and lead 

 in South Dakota and Wyoming; (4) manganese and 

 manganiferous ores; (5) recovery of secondary metals. 

 Part ii., "Non-Metals": — (i) Mica; (2) fuel briquet- 

 ting; (3) sand-lime brick; (4) sulphur, pyrite, and 

 sulphuric acid ; (5) mineral paints ; (6) slate ; (7) potash 

 salts; (8) fuller's earth; (9) cement industry; (10) 

 feldspar; (11) talc and soapstone; (12) barytes ; (13) 

 silica; (15) abrasive materials; (16) phosphate rock; 

 (19) sand and gravel. 



It need scarcely be said that the high standard of 

 accuracy, and abundance of detail, that we are accus- 

 tomed to find in the statistical publications of the 

 United States Geological Survey have been fully main- 

 tained. 



IRON IN ANCIENT INDIA. 



P>ULLETIN No. 12 of the Indian Association for the 

 -'-' Cultivation of Science contains an interesting 

 article on iron in ancient India, by Mr. Panchanan 

 Neogi, professor of chemistry in the Rajshahi College, 

 Bengal. The author discusses the question whether 

 iron was known in the Vedic age, and advances 

 evidence, chiefly based on the Rigveda, in favour of the 

 view that iron was known and used between 2000 and 

 1000 B.C. Whether absolute reliance can be placed 

 on this evidence, especially as to the dates, may 

 be open to question, but the find of ancient iron 

 weapons on a burial site in Tinnevelly proves that iro:i 

 was undoubtedly known in India in very early times ; 

 while the piece of iron slag unearthed at Bodh-Gaya. 

 shows that iron smelting had been carried on in 

 the third century B.C., and the iron clamps found in 

 a temple on that site, to which the date 400 to 

 600 A.D. has been assigned, bear evidence to a con- 

 siderable advance that had then been made in the 

 working of the metal. As regards the metallurgy 

 of the metal, wrought iron was produced, as in all 

 countries in early times, by the direct process from 

 ores by smelting them in small blast furnaces without 

 the intermediate production of cast-iron. The well- 

 known iron pillar near the Kutub Minar, Delhi, and 

 the rectangular iron beams of the temple at Puri, 

 to which the dates 640 A.D.-1174 a.d. have been 

 ascribed, are cited as examples of the scale on which 

 iron forgings were made and of the remarkable skill 



NO. 2358, VOL. 94] 



attained by the workers in the metal. These gigantic 

 forgings were constructed by welding together small 

 blooms of iron, a method which continued to be 

 practised in China and Japan until the middle of last 

 century. The Delhi pillar has not rusted to a 

 marked degree, and this resistance to corrosion is 

 ascribed by the author to the composition of the 

 iron, which is free from manganese and sulphur, and 

 contains a tolerably high percentage of phosphorus. 

 The paper also includes an interesting account of 

 the method of making wootz or Indian steel as prac- 

 tised in India long prior to the manufacture of crucible 

 steel in Europe. 



AN ALL-METAL DIVING DRESS. 



npHE Engineer for December 11 contains an account 



-*■ of an all-metal diving dress invented in the 



United States of America by Mr. Chester E. Macduffee. 



This dress is the result of about five years' experiment, 



and is now claimed to have reached a practical stage. 



MacdufTec Diving Diess. Diver coming up after submergence, 

 t rom the Engineer. 



Divers have used this armour at a maximum depth 

 of 212 ft., and could have gone deeper had more. water 

 been available. The dress is made of an aluminium 

 alloy of great strength, and weighs empty about 

 480 lb. ; its very considerable displacement gives it a 

 good deal of buoyancy when in the water, and necessi- 



