AMERICAN INSTITUTE. 465 



cartVs crust, wliich often happens, the ehai-acter of the mineral changes 

 immediately ; so that one variety prevails when the formation is in one 

 direction, and a different one when it deviatas from that line, plainly show- 

 ing that there is some law of polarity working not generally understood, 

 and I have no doubt but that electricity has much to do with it- 

 Mr. Tillman opened the discussion of the regular subject of the sitting, 

 *'' Building materials of this State," by adverting to the known excellence 

 •of some of our marble quarries, conveniently^ situated for us, and asking 

 some member to say why they are not used ? I see a gentleman who can 

 tell us. 



Professor Cyrus Mason, — Meaning me, sir ? I profess to know but 

 little ; but 1 do notwithstanding know that we lose enormous sums of money 

 by means of want of knowledge of the materials proper for building- Bos- 

 ton began with the granite, from her hills, which, however imposing to un- 

 studied observers, is with its mechanical structure of feldspar, mica and 

 quartz, not durable. Buildings of it scarcely fifty years old, show decay. 

 Bricks are very superior to any sand stones, which are also mechanical in 

 structure. Sands cemented with a little iron, failing rapidly, wherever 

 shady and moist, forming a soil for mosses, which aid the power of weather 

 to scale it, and soon disintegrate it — even the very best of it, as in Trinity 

 church, at the head of Wall sti-eet, or the rear of our city hall, I call on 

 members for all their strength, to give such a course to the builders, at least 

 of all public edifices, as may leave monuments for ages to come, I desire 

 that a committee may be appointed to examine and report on this subject. 

 Some of our marble buildings are made of a, marble containing so much iron 

 as soon stains its surface — as in Barnum's museum, the University, and others. 

 The history of brick will necessarily be embraced in this examination. 

 in the new country west of Milwaukee, necessity produced an artificial ma- 

 terial, that is sand and lime very intimately mixed, pressed into moulds of 

 required forms, of which firm, tight and dry walls have been made. Like 

 material has been made in Connecticut, and in New Hampshire, where they 

 condense it by pressure. The combination consists of nine parts of sand to 

 one of lime, and the pressure stated to be five thousand pounds weight. Par- 

 titions are well made of it. It is very valuable to those districts where 

 timber, and clay for bricks are scarce. England first burned her bricks in 

 the 14th century. Buildings of stone and these bricks were decayed, that 

 is the stone, a hundred years ago ! while of course the bricks were just as 

 good as when they were taken from the kiln. Great error exists in 

 reference to machines for making brick. Great pressure used on the 

 clay, leaves the edges of the brick brittle, they readily lose the proper 

 sharp edges, and their faces soon begin to show the small pox, being pitted 

 by the dropping out of small granules- Mortar wants our study, Stew- 

 art's front structure has nearly ever^' stretcher broken .' He employed 

 Brigaldi, an artist of great merit in drawing and painting — superintending 

 a school of design. Mr. Stewart saw some of his work, was highly pleased 



[Am. Inst.] 30 



