﻿CLAYS FROM LUZON. 431 



which is almost identical with that of Meissen porcelain, given by Binns 24 

 as follows : 



Silica. 



Alumina. 



Iron. 



Lime. 



Magnesia. 



Alkalies. 



58.5 



35.10 



0.80 



0.30 



Trace. 



5.00 



The common clays of Luzon are already used in several places in 

 the manufacture of brick and crude pottery. For example, the brick- 

 kilns at Mandaloyon and the one near San Pedro Macati, on the 

 Pasig River near Santa Ana. each of which employs from ten to twenty 

 laborers, turn out from one to three thousand bricks a day per kiln. 

 Sample number 33, Table T, is an analysis of the clay used in Mandaloyon. 

 No sand is added to it before molding, but the whole bank is broken down, 

 mixed by the tread of carabaos, and used for the bricks. This makes 

 the composition slightly different from the analysis given, but tests of 

 the shrinkage and tensile strength show that its physical properties 

 remain almost unchanged. 



At present there is no fine pottery being made on this island. There 

 is a factory near Manila which manufactures plates, cups, saucers, bowls, 

 etc., and for these about 20 tons of the good Laguna kaolin are used 

 every year. 



The kaolin from Calamba employed in this pottery is too plastic 

 when used alone, so it is recomposcd by mixing with two varieties from 

 Bulacan and Ilocos Norte Provinces, respectively. Experiments are now 

 being made with Mariquina clay. The quartz used is picked from the 

 gravel which is being dredged from the Pasig River near by ; the asbestos 

 which is placed in a layer between the plates in burning is from Zarubales 

 Province. It is of very poor quality, probably a much better variety may 

 be obtained from Ilocos Norte. 25 The ware is dipped once for the 

 siliceous glaze before it is burned. The breakage is small, not exceeding 

 2 or 3 per cent during the molding, drying, etc., and 4 or 5 per cent 

 during the burning. Some of the ware is decorated in simple designs. 

 It is difficult to describe the final product, which is quite similar to the 

 English Dolton ware. This establishment employs eight men and the 

 output is about 5,000 pieces per month. Formerly this ware had a large 

 sale in Manila, but now is sold mostly in the provinces. There are two 

 men still engaged in bringing kaolin from Laguna Province to the Manila 

 market. The two sources are near Calamba and Los Banos from which 

 are brought about 75 or 100 tons per year, respectively, it sells at 

 wholesale in Manila for from 1*23 ($11.50, United States currency) to 

 P32 ($16, United States currency) per ton. It is usually bought in 

 10-pound balls and finds its principal purchasers among the Chinese of 

 Binondo, who make of it a sort of whitewash. The retail price varies 

 with the supply from 25 centavos (12| cents, United States currency) 



- 1 Ceramic Technology, London (1807), 19. 



-■Smith, W. D.: This Journal, Sec. A, Gen. Sri. (1007), 2, 145. 



