EXTRACTS FROM COMMUNICATIONS OF THE EXPERIENCE 



OF Thomas Bowley ESQ. OF DUBLIN WITH 



DOUBLE GLAS S HOUSES, 



COilPILED EY 



Mr. ROBERT WARNER. 



(Voir le Compte Rendu de la Séance du 10 Avril 1865, pag. 312). 



The advantages of double glazing are at lea.st fourfold. 



Before we proceed to describe them we will state in what the 

 principle of double glazing consists. 



1^'. There must be a double glass roof, and double sides will 

 carry out the principle more completely. 



2"^. It is absolutely necessary that the space between the two 

 glass roofs should be perfectly air tight, as this encloses a body of 

 air which becomes a non-conductoi' of heat or cold. 



The l'oof is constructed with ordinary wooden rafters 4< feet 

 apart,with3 light iron sashes between. The inner glass is commonly 

 21 inches per foot; it is put in about one inch on the underside of the 

 rafter, so that the rafter being about 6 inches depth, 5 inches of rafter 

 is outside the inner glass. On thèse projecting rafters the outer roof 

 rests. The outer roof consists of simple franied sashes 4 feet wide, 

 and for the convenience of moving are made in two lenghts. They 

 are glazed with the same glass as the sides, viz. fine ribbed glass 

 called Hai'tley's i-ough plate. Thèse simple sashes are fixed on the 

 rafters by screw bolts, so as to be easy to move. Thus we hâve the 

 inner and outer glass 5 to 6 inches apart. The distance is not impor- 

 tant either 4 to 6 inches will do, but it is of the iitmost importance 

 that they fit close so that there shoiild be no circulation of air be- 

 tween. The glass is cari-ied up to withinl foot of the top of the ridge, 

 which foot of space is fitted with wooden shutters foi' ventilation. 



The Fernhouse is 48 feet long and 60 feet wide and 21 feet high, 

 2 rows of 4 inches pipe is sufficient to heat ail this large body of air. 



AâAjantacjes. 

 l^t. Prevents any excess of heat by day. 

 2""^. Aflfords a great protection from cold by night. 



