464 CEMENTS, LIMES, AND PLASTERS. 



Concerning the French flints, Mr. Thackara writes as follows: 



"By the action of the sea on the base of the chalk cliffs, which form 

 the coast-line of a portion of the Department of Seine Inferieure, frag- 

 ments of the rock are detached. Those which are composed of the 

 flint found in the cliffs, on account of their hardness, are not reduced 

 to sand by the trituration arising from the movement of the waves 

 or tidal currents, and become what are known as sea flint pebbles. 

 These are gathered on the beaches between Havre and St. Valery-sur- 

 Somme, a distance of a little over 100 miles. Those which are nearly 

 spherical in shape are carefully selected and are used in the Alsing sys- 

 tem of cylinder grinding, which is becoming so generally employed 

 for pulverizing cement, chemical and pharmaceutical products, etc. 

 The others are bought by the potteries for making ordinary porcelain 

 ware after being calcined, ground into a fine powder, and mixed with 

 china clay. 



" According to the official custom-house statistics, there were 13,592 

 tons of flint pebbles exported from France during 1900, valued at 

 $39,348. The value of the declared exports of these stones from France 

 to the United States for the fiscal year ended June 30, 1900, was $16,743, 

 of which $3849 were shipped from Havre, $4458 from Boulogne, and 

 $8436 from Dieppe. 



"The prices of the flint pebbles for use in the potteries range from 

 5s. 3d. ($1.27) to 12s. ($2.92) per ton f. o. b. in bulk at Fecamp, St. Va- 

 lery-en-Caux, Dieppe, T report, St. Valery-sur-Somme, and Havre, accord- 

 ing to quality and to the port from which they are shipped. For the 

 selected pebbles the prices vary from 35s. ($8.52) to 42s. ($10.21) f. o. b., 

 packed in barrels or bags, packing included. 



"The rate of freight from Havre or Dieppe to New York averages 

 10 francs ($1.93) per ton of 1000 kilograms (2204.6 pounds). 



"French flint pebbles are shipped to England, Scotland, Norway, 

 Sweden, Russia, Spain, Japan, and the United States. In the Baltic 

 ports they have to compete with the pebbles exported from Denmark. 

 Germany is now using silica sand from the river Rhine for pottery 

 purposes, which replaces the flint pebbles. The French pebbles also 

 have to compete with those collected on the English coast at Newhaven, 

 Shoreham, and Rye, with the chalk flints shipped from London, and 

 with the Greenland selected pebbles." 



For the following analyses of tube-mill pebbles, from lots furnished 

 by various importers, I am indebted to the chemists named below. 



1903. Thackara, A.M. Export of sea flint pebbles from France. U. S. Consular 

 Report No. 1231. Jan. 6, 1902. 



