GLAZING, 



51 



of putty are objectionable, inasmuch as they are apt to crack unless they 

 be painted soon after they ai'e used; they are also difficult to remove 

 when it becomes necessary to repair broken glass. 



The most approved modes of glazing are ciurihnear, lap glazing, re- 

 versed curvilinear, rhomboidal, perforated shield, entire shield, fragment, 

 leaden lap, and common sash glazing. The first and last are certainly 

 the best for our pm-poses. 



An ingenious, and, we think, a very useful mode of glazing ^vas pubhshed 

 some years ago in the Transactions of the Horticultm-al Society, and is 

 the invention of Mr. John Read, of the Regent's Ch-cus, PiccadiUy, weU 

 known to horticulturahsts for his exceHent patent syringes. " :\It, 

 Eead observes, that in the usual way, the sui-face of the putty being entirely 

 exposed, soon looses its tenacity, and partiaHy separates from the bar, 

 thereby admitting wet into the house and hastening the decay of the 

 wood. To obviate these defects, Mr. Read's 

 sash bar has a groove on each side to receive the 

 glass and putty and the top is planed ofi", leaving 

 it slanting both ways, as is shown in the 

 annexed sketch, which is a section of the bar 

 and glass. There is not more difficulty in re- 

 pairing the glass in hghts, or roofs with bars of 

 this form, than in those made in the usual way, 

 as a narrow chisel, like a mortice chisel, cuts out 

 the old putty with great ease/' 



FORM OF GREENHOUSES. 



Greenhouses may be of various forms and shapes, but the further 

 that the parts deviate from straight lines, the more will the expense be 

 increased, on account of the waste of material and extra labom- in work- 

 manship. Chcular, domed, and cui'rilineai' houses are all liable to the 

 above objection, and, in addition, are not easily veutHated. The ordinary 

 form of straight roofs, or that of a span roof, is, in oiu* opinion, the most 

 economical and fittest for all pm'poses. It may not be unimportant if we 

 state briefly some opinions of much greater weight than our own on this 

 subject, both for and against such foi-ms of roofs. 



The iutelhgent Thomas Andrew Knight, Esq., observes, that the plan 

 recommended by the late Sir George I^rKenzie, Bart., for forcing 

 houses, although exceedingly interesting, contains some defects wliich 



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