G74 Transactions of the American Institute. 



to keep them in their original position. Next, the boxes are filled 

 with a mixture of rubbish, or broken stone, and the above described 

 mortar. But if the waves or the violence of the sea does not permit 

 of keeping the boxes in their position, a solid platform must be 

 thrown up from the land or shore dam, which is to be constructed for 

 one-half of its length in such a manner that it will form a level with 

 the sea, while the outer half should be sloping. Walls should then 

 be erected along the platform of one foot and a half in width, and 

 of the same height as the latter. The intermediate space is then 

 filled up with sand. On the surface thus produced, a block cf the 

 necessary dimensions is formed, which, after its completion, is left to 

 dry for not less than two months ; but after that, the breast wall, 

 which affords a hold to the sand, is torn down, the submerging of the 

 block being left to the waves that wash the sand away." 



From the time of Pliny (who reproduces the report of Yitruvius) 

 up to the fifteenth century, no further mention is made of hydraulic 

 mortar. During the fifteenth and sixteenth centuries, Leon Battista 

 Alberto, the founder of the Renaissance, Palladio Scamozzi, and 

 Philibert De Lorme, made precisely the same reports as the Latin 

 authors. Since the latter part of the seventeenth century, the Dutch, 

 the condition of whose country render hydraulic constructions especi- 

 ally desirable and necessary, first used domestic (in place of Italian) 

 cement, from the neighborhood of Coblenz. Next to Holland, the 

 application of water mortar was first resorted to in France and Eng- 

 land ; but up to the middle of the eighteenth century, nothing further 

 became known about its use and application than what had already 

 been familiar to the Romans ; for the work of the celebrated engineer 

 and architect Belidor (Architectura hydraidica, Paris, 1753) contains 

 nothing of interest except that which had before been explained by 

 Vitruvius. Since the end of the last century, however, a lively and 

 general interest in the subject has manifested itself. 



The impetus to new experiments with hydraulic mortar was given, 

 in 1791, by the celebrated John Smeaton, the builder of the Eddy- 

 stone light-house. " The Eddystone light-house," says Michaelis, in 

 his excellent treatise on hydraulic mortars, "is the corner-stone on 

 which the knowledge of hydraulic mortars has been built ; it is the 

 pillar of modern architecture. Not only to mariners, but to the 

 whole world, this pharos has become a landmark of most beneficent 

 effect." 



Smeaton was required to solve the problem of constructing a high 

 and colossal structure, exposed to the fury of a tremendous sea : for 



