and the Ufe of Liquid Pitch. 129 



inches and a half lo ihree in thicknefs; the covering on- 

 which it is placed oiu'Ju to be nioillened with milk of quick- 

 hme ; and the cement mii(l be preflTed down clofely with' 

 the trowel, takinir care to beat it with the fliarp edge of that 

 inftrumenl. It islfmootbed by the back of the trowel flightly 

 moiftened. The fnrface of the cement muft be again prelFed 

 down, to burv thecoarfer parts and render the whole fmooth. 

 When the (irfl band is finilhed the workman proceeds to a 

 fecond, and the two bands niuft be carefully united to pre- 

 vent their feparation. 



This cement foon dries, and at the end of an hour can fuf- 

 tain a (iroug preflurc. It muft, however, be left feven or 

 eight davs.; after which the farface of it is to be {lightly 

 moiftened, and then prcfTed down and fmoothed by means 

 of flat (tones in the fiime jnanner as marble is poliflied. This 

 lafi: precnntion is eflentially neceffiirv, and the folidity /)f the 

 cement will depend on the care with which it has been per- 

 formed. When the terrace has been confl;ru£ted in this 

 manner, the aggrca:ation of the cement becomes ftronger, 

 and its pores are fmaller and lefs numerous. 



In order that the cement may fucceed perfeftlv, it mufi: 

 l)e made during the great heats of July, that the fnpi^rabun- 

 dnnt water may c jporate, and that it may be perfe6tlv dry 

 before the autumnal rains. At the end of Anyurt, boil pitch, 

 fuch as that ufed for fhips, and fpread it over the cement by 

 means of large bruflics. As this coating woidd reuder the 

 cement not fit to be touched during fummer, this inconve- 

 nience inav be remedied in the following manner : — Take 

 lime, flaked in the open air and reduced ti^ fine powder, and, 

 having Ipriuklcd it over the pit'-h, remove, by means of a 

 broom, the fupcrfluous part of the lime which docs not ad- 

 here to it. This lime, by combining with the pitch, will 

 form with it a very thin ftra'uin of cement fimilar to the 

 inaUha of the Roman';. Ai thc-bi'ginninn; of 06lobcr a fe- 

 cond ftratum f)f piich and lime mufl be laid on. 



The fcc'.-nd method of cniplo\ing the cement is to phce it ' 

 immediately over the ftratum of brick and clay, and then to 

 cover it with a pavtiuf^nt of brick, mortar, and fand. I have 

 two terraces, fifteen fathoms in length and one and a half in 

 breadth, which appear to me to have the grealeft folidity. 

 They are not fo beautiful! as Uiofe where the cement covers 

 the brick ; but they can ftand every kind of fridlion or pref- 

 fure. 



After making a ftratum of clay and fnnd, fpread over it a 

 ftratum of cement four inches in thicknefs, well beaten, and 



Vol. XIV. No. 54. I add 



