0)1 Meriarr, Lime WaUr, Cementj, ift;. ^Op 



V. 



A Memoir on Mortars^ Water Limey Cements, and Pauzzolana. By CiT. GuYTOlf*-' 



w. 



E find in many publications accounts of procefles for the preparations of mortars and 

 cements; enquiries into the compofition of thofe employed by the ancient in edifices ftill 

 refpited by time ; experiments to determine the condition of their folidlty in the different 

 circumftances ; obfervations on the materials proper to each of the feveral ufes ; and de- 

 fcriptions of the charafters. It has appeared to me that by colle£ling and comparing the 

 fa6ls and inferences, we might obtain a fmall number of truths no longer fubjeft to dif- 

 cuffion, which cannot be rendered too familiar to mankind. This is the obje£t of the 

 prefent memoir, in which I fliall alfo ftate feveral experiments hitherto unpublilhed. 



Loriot Afortar. 



In 1775, the late M. Loriot direfted the mixture of one -fourth part of powdered lime 

 in a good mortar, made as ufual of lime and fand, as the eflential conditions for obtain- 

 ing buildings as folid as thofe of the ancient Romans. See his Memoir, Journal de 

 Phyfique, III. 231. 



Having obferved that the pulverization of the lime is a painful and even dangerous 

 operation for the workmen, who, notwithftanding every precaution, were fubje£t to bleed- 

 ing at the nofe. I propofed to have the lime covered till it became fpontaneoufly flaked 

 into powder, and then to calcine it again in a fmall furnace, and ufe it hot. 



This procefs is explained at full length in a memoir printed in the fourth volume of the 

 Journal de Phyfique, page 481. It has been frequently ufed in the large way, and always 

 with the moft perfeft fuccefs ; which is not to be wondered at, when we confider that two 

 very defirable conditions are thus obtained, namely, that the lime is frefh and in very fine 

 powder. 



The defcription of the oven, with plans, fe£lions, and profiles. Is to be found in an in- 

 ftrudion printed in 1775, by order of government, and in the Journal de Phyfique for 

 Oftober of the fame year, Vol. VI. page 31 1. The dimenfions are fufiicient to afford an 

 uninterrupted fupply to the labour of a nUmber of workmen, and the proportions of the 

 compofition of the mortar, which were thought to be the beft, were : 



Fine filiceous land - - - . o. 



Cement of well-baked bricks , - - - o. 



Slaked lime - - - - ' - O. 2 



Lime fpontaneoufly flaked, and again calcined - o. 2 



3 



3 



10. 



Mert, 



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