GLASS STRUCTUEES AND APPLIAKCES. 



213 



Glazing with Putty. — ^Previous to the re- 

 moval of the tai'ifi on glass the squai-es -wcro ex- 

 tremely small, and the sash-havs, or astragals, were 

 so closely placed as to greatly intorfoi-e with the free 

 passage of light ; moreover, those made of deal were 

 much heavier than is now considered necessary, 

 notwithstanding the fact that much larger and 

 thicker panes ai-e now used. Add to this the 

 numerous laps choked with dirt, or perhaps carefully 

 dosed with putty, for the twofold purpose of ex- 

 cluding cold air and preventing drip, and it is by no 

 means difficult to imagine a roof of the woret descrip- 

 tiou that could be devised for horticultural purposes. 

 In such a roof it has been calculated that every 

 100 ft. of glazing presented fi-om 25 ft. to 30 ft. of 

 opaque surface, through which not a single ray of 

 light could penetrate. Fully alive to the disad- 

 vantages under which they laboured, horticulturists 

 introduced iron, copper, and zinc for sash-bars ; but 

 these materials did not greatly improve matters, as 

 may be gathered from Fig 32, which is drawn from 

 a portion of a light still in existence, made seventy 

 years ago. At that time gla.zing without fore-putty 

 had not been thought of ; yet, when thorouglUy well 

 bedded, which is the great seci-et of putty-glazing, 

 and two coats of good white-lead paint are laid on 

 «ach side of the square, from one-eighth to a quarter 

 of an inch broad, the first step towards improvement 

 has been secured. One of the great evils of fore- 

 puttying is the predisposition to drip, which is 

 brought about by the constant pressure of moisture 

 behind the putty when it begins to part from the 

 tongue of the sash-bar, as it soon will when used of 

 inferior quality, or if the wood is not dry and well 

 seasoned. Once let into the "bed, the wood swells, 

 and frost causes the putty to expand, when, the 

 glass being non-elastic, itnatm-ally breaks under the 

 great pressure. Of equal value is this omission of 

 the fore-putty on metallic roofs, as expansion goes 

 on more freely over every part of the bai% and there 

 being no decaying matter to prevent it, water passes 

 quickly awjiy. 



Metallic roofs were at one time greatly condemned 

 on accoimt of the loss from breakage ; but this arose 

 from what is termed hard glaring, that is, cuttmg 

 the glass too large for the openings. This part of 

 the mechanic's business is now better understood, 

 and where one-eighth of an inch of play is left on 

 «aoh side, breakage is not more frequent in roofs of 

 metal than of wood. It may not be out of place to 

 mention that mineral or anti-corrosion paint used as 

 a priming coat for preceding glazing has, in my own 

 experience, proved greatly superior to lead of the 

 best quiilitr. and being cheaper it is worthy of ex- 

 tended use." Some twelve y&ii-s ago a Peach-house 

 was primed with it; the sqmu-es (U in. by 20 iu.) 



were well bedded, but not fore-puttied, and every 

 part of the roof is still sound and free from drip. 

 Since that time the roof has received the triennial 

 course of oil and lead painting, and every inch of 

 sash-bar is as firm and good as it was at the end of 

 the first year. "When anti-corrosion paint is used 

 it seems to penetrate the wood Hlce creosote, and 

 to become part and pai'cel of the fibre, from wHch J 

 it never separates. The drawback, in the fiist' 

 instance, is its roughness of surface, but this becomes 

 plain and smooth after it has received one or two 

 coats of oil paint. 



Modern Glazing. — For some time after the 

 tariff was removed, horticulturists, at all times very 

 anxious to get rid of perishable facing, were un- 

 decided as to the best mode of accomplishing this 

 object. Manufacturers commenced supplying them 

 with an article imperishable, except by fractm-e, at 

 a price for quantity and quality ti-uly surprising, and 

 all lovers of gardening began to indulge in the pos- 

 sible luxury of a bit of glass. Market gardeners, 

 private growers, and nurserymen saw their way to 

 mpid extension ; but the builders, for the nonce, 

 found themselves nonplussed by the producers. A 

 good article was placed within their reach, an arti- 

 'cle which would enable them to set the elements at 

 defiance, as they could bring the vegetation of the 

 Antipodes to grow and flemish at then- very doors ; 

 but the perplexing problem, " How are we to apply 

 it so as to get rid of this perishable oil and chalk ? " 

 presented itself. The constant hacking out of » 

 broken square, often involving the fracture of two 

 more in the performance of the operation, began, 

 however, to quicken men's brains, with the usaal 

 result, and systems of glazing innumerable, some, 

 good, some bad, spi-ang into existence. The life of 

 some was fleeting, as they possessed no practical' 

 value. 



That many of these inventions are a great ad\-ance 

 there can, however, be but little doubt, and we will 

 endeavour to notice as many of the best as the limits 

 of these pages will allow. 



Smrd's Si/steiiu—One of the most important moves 

 in a new direction is the system invented and pai 

 tented by Mr. Beard. It has now been in use for 

 some time, and forms the keynote on which other 

 inventors and manufacturers have played; the object 

 in every instance being a maximum of light, com- 

 bined with a minimum exposm-e of perishable mate- 

 rials to the action of the elements. It possesses 

 sevenxl advantages which the ordinary mode of 

 glazing with putty does not offer, and one of the 

 most important is the faciUty with which the whole 

 of the glass can be taken out and put in ag-.iin, 

 should it be found necessary to remove the house. 



