December 20, 19 17] 



NATURE 



305 



The pottery newly discovered in Shensi, and forming 

 the subject of our investigation, is a distinct group, 

 which, as maintained repeatedly, was not turned out 

 under the Han, but long afterwards, at the end of 

 the third century a.d. In its form and design it is a 

 direct descendant of Han pottery, but its glazfe, as 

 proved by analysis, is porcelanous. For this reason 

 it has been styled " Han porcelanous pottery." 



Dr. Mellor mentions only the analysis of the green- 

 blazed Han pottery, which has no connection whatever 

 with the porcelanous material analysed. The body of 

 this Han fragment is a coarse red earthenware, which 

 can in no sense be considered porcelanous. Certainly 

 the porcelanous body analysed does not appear porce- 

 lanous to casual inspection. The true character of the 

 ware appears only when a slide is prepared and 

 examined under a petrographic microscope, when the 

 porcelanous character becomes so strongly evident that 

 mistake is impossible. The frothiness of the body 

 which masks its porcelanous features from macro- 

 scopic observation is also plainly visible in the slide. 



We are not at all interested in the philological inter- 

 pretations of the Chinese term is' e. Our identification 

 of this new pottery with the early is,' c of Chinese 

 records rests solely on archzeological arguments, not 

 on any philological considerations. 



B. Laufer. 



H. W. Nichols. 



Field Museum, Chicago, November 8. 



I AGREE with most of what I have read in Messrs. 

 Laufer and Nichols's work which made any impression 

 on my mind, and I also agree likewise with what is 

 said in the above letter. I except the impression con- 

 veyed by the title, and in some parts of the text of the 

 excellent brochure, as well as in the present letter, 

 namely, that the Han pottery (body and glaze) referred 

 to can be called porcelanous or the froth of porcelain. 

 As they say, it is stoneware — and is not a particularly 

 good variety at that. If Messrs. Laufer and Nichols 

 will apply the petrological test to a good class of "acid 

 brick," such as is used in the Glover's tower of a 

 sulphuric acid works, they will find just as much, 

 or even more, ground for stating that these bricks are 

 porcelainic. I have compared the two bodies and would 



>te in favour of the bricks. Similar remarks would 



-;o apply to ancient and modern ware made from the 

 - i-called vitreous clays when fired, for thev, too, have 

 a similar character, and many have a similar chemical 

 composition. Ware like the so-called Bottcher, or Bott- 

 ger, "porcelain" should not be called porcelainic — ex- 

 cepting, perhaps, as a "registered trade mark" or in 

 metaphor. Nor is it anv real contribution to history 

 to call it the precursor of porcelain in Europe when we 

 recall that numerous analogous cases must have been 

 Jn the alchemist's hands centuries before Bottger's 

 time. The analogy is surely valid also in China. 



In my comments I tried to convey the impression 

 that Messrs. Laufer and Nichols's suggestion was not 

 !n accord with the technical concept of porcelain in our 

 country, but I can quite understand that thev mav be 

 working with another concept of porcelain which 

 enables them to apply the term as an adjective to the 

 pottery in question. It would be better if these points 

 were threshed out before a technical society, since this 

 is scarcely the place to make an attempt to develop a 

 standard definition of porcelain uniformly acceptable. 

 The main discussion would, I take it, work round the 

 body — the glaze />cr se would give less trouble. 



Nearly all beginnings are obscure, and Messrs. 

 Laufer and Nichols have made a meritorious contribu- 

 tion to the subject which in the past few months I have 

 strongly recommended to many students. 



J. W. Mellor. 



Stoke-onTrent, December 6. 



NO. 2512, VOL. too] 



MAGNETIC AND ELECTRICAL 

 OBSERVATIONS AT SEA.^ 



THE handsome volume before us is principally 

 concerned with the magnetic and electrical 

 observations made at sea by the Galilee (1905-8) 

 and the Carnegie (1909-16). It also includes some 

 observations made on shore in connection with the 

 cruises of the two vessels. Some of the contents 

 appeal only to a narrow circle, but much is of 

 g-eneral interest. Thus we have the " charter 

 party " by which Mr. Matthew Turner, managing 

 owner of the brigantine Galilee, of the net ton- 

 nage of 328, contracted to maintain the vessel 

 tight, staunch, sound, strong, and seaworthy with 

 a sailing master, two mates, six seamen, and two 

 cooks. Then we have the instructions issued by 

 the director of the Department of Terrestrial 

 Magnetism to the master before each cruise, the 

 report of the master, the daily log, and particulars 

 of all the instruments on board. The parts of 

 most general interest are the descriptions of the 

 observational instruments copiously illustrated in 

 the plates, the reduction formulae, the tables of 

 observational results, including the graphical 

 illustration on pp. 424-29 of the errors in current 

 magnetic charts, and the discussion of the electri- 

 cal observations. A certain amount of the mate- 

 rial has already appeared in a less complete form 

 in earlier publications, but the present volume 

 collects everything together and shows the gradual 

 development of ideas. 



The portions of the volume relating to the Gali- 

 lee arid the Carnegie magnetic observations are 

 indexed separately, and there is a third index for 

 the electrical observations, so that the volume is 

 practically in three parts. The Galilee seems to 

 have been an excellent sailing vessel, and as suit- 

 able a one for magnetic observations as could have 

 been hired in 1905. But, like any ordinary vessel, 

 she had a magnetic field of her own, the elimi- 

 nation of which required frequent "swingings" 

 of the ship and all the elaborate procedure which 

 renders magnetic work at sea so burdensome. 

 With the experience they gradually acquired, Dr. 

 Bauer and his coadjutors gradually saw their way 

 to the construction of a ship practically free from 

 iron. Plans were prepared in 1908 by Mr. Gielow, 

 of New York. The keel was laid in February, 

 190^. In June, -1909, the Carnegie was duly 

 launched and christened, and on August 21 of the 

 same year she entered on her trial cruise. With 

 equipment she cost about 115,000 dollars. She is 

 primarily a sailing vessel, but with auxiliary pro- 

 pulsion. The motive p>ower is derive"d from an 

 internal-combustion engine of 150 horse-power, 

 working with gas produced from anthracite coal. 

 The engine itself is essentially bronze, but steel 

 of a total weight under 600 lb. had to be used for 

 certain parts. The Carnegie has been " swung " 

 on various occasions, but, to all intents and pur- 



1 Re-^earches of the Department of Terrextrinl Maenetism. Vol. iii., 

 "Ocean Magnetic Observations, 1905-16, and Reports on Special Re- 

 searches." Bv L. A. Hauer, Director, with the coll.iboration of W. J. 

 Peters, J. A. Flemine, J. P. Ault, and W. F. G. Swann. Pp. v+447, with 

 25 plates and :?s fieures in the text. (Washington, D.C. : The Carnegie 

 Institution of Washington, 1917.) 



