270 MANUFACTURES OF RUSSIA. 



The chief basis of the matter was only laid towards the beginning- of the second 

 <inarter of the present century, in the researches of Vica. which extended in their 

 <leta,ils over the whole of that quarter of a century and more. This famous French 

 savant, after having discovered the first bases for making a clioice of the material 

 for the manufacture of the so-called natural Roman cements, and also of the artiti- 

 •cial cements, travelled over the whole of France, and pointed out to the local build- 

 ers and engineers the best localities for finding cement-making materials, and the 

 most advantageous methods of converting them into cement. At that time, however, 

 it was not everywhere that manufacturing industry and experimental science went 

 tluis hand in hand. 



When in 1825. in practical England, there first appeared, as an undoubted 

 ■echo of Vica's work, that now most important and highest branch of cement manu- 

 tacture, the production of Portland cements prepared by the then little known 

 method of strongh' calcining the material to incipient vitrification, then the evident 

 adaptability of this English manufacture to the original local material upon whose 

 properties, it seemed to many, the incomparable qualities of the resultant products 

 were exclusively dependent, was enough to guarantee to England a monopoly of this 

 manufacture for fully twenty years. Even at the time of the London Universal Exhi- 

 5jition of 1851, the English savants said with conviction that the mixture of chalk 

 and natural river silt, or the argillaceous deposit of some rivers running over clay 

 .ind chalk, which they employed for the manufacture of Portland cement, could not 

 he successfully replaced by any other artificial mixtures of limestones and clay; they 

 said furthermore: «It is not difficult to procure artificially mixtures of limestone and clay, 

 which are less costly than the natural kinds, though not equal in value* (Report ot 

 the Juries p. 573, Exhibition 1851). The English Portland cement became an impor- 

 tant article of export, and very large quantities were furnished to the shores of the 

 Arctic Ocean, Baltic Russian ports, and to France and Paris, where the English cement 

 was particularly used in large quantities in the construction of the large northern ports. 

 This state of aftairs continued to the middle of the present century, and even in 1856 

 the experts of the Paris Universal Exhibition certified that, « notwithstanding 4he 

 greatly extended use of the English Portland cement its manufacture had, contrary 

 to all expectations, remained but little studied». This closes the first period of the 

 history of the manufacture of cements. 



During the fifties, the fundamental data, which were required to guide the 

 development of this industry, began to increase rapidly, and at the same time the 

 first endeavours were made to establish the manufacture of Portland cement on the 

 Continent. It was proved in 1850 to 1851 that, when hydraulic limestones of a suit- 

 able composition are calcined to incipient softness, they give cements which conglom- 

 erate slowly, but attain an immense hardness in the course of time. 



The manufacture of Portland cement in France in was first started 1850 at 

 Boulogne-sur-mer, by Messrs. L>upont and Demarle; and almost simultaneously, in 

 1852, in Germany at Stettin. The manufacture at Stettin Avas founded upon a pro- 

 cess elaborated by Dr. Bleibtree of Bonn. The process was similar to that practised 

 in England; the cement was prepared from chalk and clay, extracted in the neigh- 

 bourhood of Stettin. At that time England, recognizing its monopoly in the manu- 

 facture of cements, and the importance of this material for marine works, ceased 



