MINING. 



coast is estimated at 5,700,000 hectoliters, distributed as stated 

 above, over 6,364 hectares of salt gardens, making an average pro- 

 duction of 895 hectoliters to each hectare during the seventy or 

 eighty dry summer days. This amount does not compare with the 

 returns from the salt gardens of equal area on the Mediterranean 

 coast. It must be especially borne in mind, however, that the 

 climate of the latter, with its dry air and rainless summers, is in- 

 comparably more favourable, and therefore the production can be 

 carried on in an entirely different way from that of the eastern 

 monsoon district with its numerous summer rains. 



Alum, Jap. Mio-ban (Miyo-ban) has been known for at least 

 1,200 years in Japan, and is used there, as with us, as a mordant in 

 dyeing. It is frequently found native in a white earthy decom- 

 position of volcanic rock, which has taken place by the action of 

 solfataras. This Ji-nen-han or natural alum is extracted, and the 

 pure crystals are formed in the solution. It is generally called Ban- 

 seki or Han-seki, alum stone, but is not to be confounded with it. 

 I saw beautiful alum at an Exhibition in the spring of 1875 at 

 Funai, the capital of the province of Bungo, which is considered 

 the principal place for its production. Shinano, Kotsuke, and Hida 

 are also mentioned for their alum. 



Porcelain stone. Kaolin, Potter's clay. A number of different 

 products of the decomposition of felspathic rocks are used in the 

 extended, and in some of its branches highly developed, pottery 

 industry of Japan. They are called in Japanese, Ishi, stone, and 

 Tsuchi, earth, according to their nature, while usually the different 

 species are designated with the name of the place where they are 

 found. We divide these ceramic materials into two classes accord- 

 ing to the agencies which have wrought the decomposition of the 

 felspathic matrix, viz. : 



I. Porcelain stones. Peculiar products of the decomposition of 

 trachyte, euritic porphyry and other volcanic rock, rich in silicic 

 acid, and appearing in unstratified masses. Their decomposition was 

 probably brought about by the influence of the sulphides of hydrogen 

 and aqueous vapour of the solfataras. To this class belong the 

 most valuable materials of Japanese porcelain manufacture, the 

 Arita-ishi of Hizen, the Amakusa-ishi of the island of Amakusa, 

 the Kutani-ishi and Nabetani-ishi of Kaga, and others beside. 



The solfatara (Jap. Jigoku, hell) affects not merely the vegetation 

 in its vicinity, but also the rock. It bleaches trachytic and doleritic 

 lava, and works an entire transformation in them. The silicic acid, 

 among other things, is often separated as stalactite, and then ap- 

 pears as a medium of a new cementation, as is shown very distinctly 

 in Amakusa-ishi. Pumpelly observed a similar transformation by 

 the solfataras, at Yu-nonai — the solfataras of Iwanai on the island of 

 Yezo — concerning which he remarks as follows : " The hot springs 

 here are in close connection with snow-white quartz porphyry. 

 This rock is impregnated with iron pyrites, which in many places 



