Kotc'S and Gleanings. 103 



ordinary houses. This house I have carried through tlie winter, at a good grow- 

 ing heat, with less than six tons of coal. The house is well protected, and lies 

 low ; but there is the broad exposure of thirty-six hundred square feet of glass 

 to the cold of twenty degrees below zero. The secret of the success is in double- 

 glazing. The roof is fixed, glazed with fifteen-inch-wide glass. The sash-bars 

 run the entire width of the house, and are three inches deep. A groove is 

 ploughed on each side of the sash-bars, a quarter of an inch from the bottom 

 side. The second surface of glass is simply slipped into these grooves, ai.d 

 butted together, leaving an air-space between the upper and lower glass of about 

 two and a half inches. Can any plan be simpler or cheaper 1 There is abso- 

 lutely no extra wood-work. The cost of ploughing the grooves and of slipping 

 in the glass is scarcely worth estimating. It may be said that the item of a second 

 entire surface of glass is a great consideration. Yes ; but it will be exceeded in 

 amount, the second year, by the saving in coal, without placing any estimate 

 upon the ease and success of management. Some one may object that a second 

 surface of glass may too much obstruct the sunlight during the short days of 

 winter. To which 1 reply, that, whenever the sun does shine, I consider the 

 slightly mitigating effect of the double glass a decided advantage to a house 

 focing south. 



If tlie inner glass become dusty, it is a slight work to slip it out, and wash 

 it. If the outer glass feels the heat less sensibly, and therefore clears itself of 

 snow less readily, the trifling extra work in removing the snow is scarcely 

 worth mentioning as an objection. I know of no other drawback to double- 

 glazing. 



And, in favor, we have a saving of from fifty to seventy-five per cent in fuel ; 

 we have perfect ease in securing the desired temperature, with much less risk 

 from extreme cold or sudden change ; we have more favorable conditions for 

 growth, with less fire-heat, and less fluctuation in temperature and in moisture ; 

 we also avoid all drip. So manifest are these advantages, it is a wonder that 

 this protection is so rarely used. Outside coverings of mats and canvas are 

 often seen ; but these are nearly as expensive as glass, and they involve continu- 

 ous and serious labor in rolling and unrolling. They are exposed to heavy 

 snows and to gales ; they are also quite perishable. Besides, they bear no com- 

 parison with double glass as a protection from cold. Inside curtains, made of 

 some thin, glazed material, are very serviceable and effectu il as a protection 

 from cold, involving less labor, and less liability to accidents from gales ; yet it 

 must be apparent that even these are by no means comparable with the tight, 

 non-conducting surface of glass, which confines the column of air two and a half 

 inches thick. I would, therefore, advise that all houses facing south, which are 

 to be used for winter-growths, should be constructed for double glass. When 

 a roof faces the east or west, the deflection of the sun's rays, by the first and 

 second surfaces of glass, might cause too little sunlight and heat for many plants. 

 Good judgment will determine how far the second surface can be used advan- 

 tageously for such houses. W. C Strong. 



