WALL-PLATES. 



549 



gentleman were of wood, and cut out by 

 hand ; but recent improvements have 

 been made, whereby they are now cut out 

 by machinery. 



Fig. 784 will show the Paxton gutter, 

 as used in the Crystal Palace. 



Fig. 784. 



Whether gutters, or valleys for conduct- 

 ing off water, should be made out of one 

 solid piece of timber, or by the combina- 

 tion of three pieces, seems to us in no 

 degree doubtful. Join the separate pieces 

 as you may — nay, even cover them with 

 copper, zinc, or lead — still they cannot be 

 rendered waterproof, and, as a conse- 

 quence, they will soon rot; and as the 

 whole roof is supported by them, the 

 durability of such roofs is shortened. Nor 

 can wooden valleys of the same dimen- 

 sions be considered as strong as iron ones. 

 The gutters which we use are of the latter 

 material ; and we find that, with less bulk, 

 and consequently less shade, we not only 

 have a much stronger roof, but one which 

 may be rendered perfectly dry. Our 

 gutters are also cast with dove-tailed mor- 

 tices along their sides, into which the 

 lower ends of the astragals fit, imbedded 

 in white-lead, and sometimes fixed in 

 with boiling pitch. — Vide fig. 785. For 

 an illustration of our metallic gutter, vide 

 Plate VIIL, and full description, vide p. 59. 



Fig. 785. 



To show the economy of mechanical 

 power in the Chatsworth conservatory 

 alone, Sir Joseph Paxton informs us that, 

 even in its original form, the sash-bar 

 machine performed the labour of twenty 

 men for one year, and consequently saved 

 £1200. The length of bars made by it 

 for that conservatory would extend 

 upwards of forty miles in a direct line, 

 making at the rate of 2000 lineal feet 

 of bars per day, and at an expense for 



attendance of only 5s. per diem • and its 

 first cost was only £20. 



The annexed woodcut, fig. 786, shows 

 the form of sash-bar, half size. The glass, 

 being let into the grooves, 

 lg * 7 * requires little putty, and, 

 when once in, is more imper- 

 vious to rain than by the usual 

 modes of glazing. In this case 

 it will also be seen that the as- 

 tragals taper both upwards and 

 downwards from the shoulder 

 to the groove, thus requiring very little 

 putty. The astragal, although thin, has 

 its strength retained by giving additional 

 depth, upon which the principle of 

 strength is well known chiefly to depend. 



The first cost of this machine is so 

 trifling, that any one intending to build 

 anything beyond an ordinary range of 

 hothouses would economise the expense 

 by the saving of manual labour. The 

 machine could easily be attached to a 

 saw-mill, thrashing-machine, corn-mill, 

 or indeed wherever there is motive 

 power on the premises. 



We have seen, in the establishment of 

 A. L. Wallace, Esq. of Edinburgh, a very 

 simple and effective machine for cutting- 

 out mortices. It was wrought by a lever 

 acted upon by the foot, somewhat like a 

 turning-lathe, and is, for framed doors and 

 sashes, an improvement which materially 

 reduces the expense of their construction. 



An amazing amount of prejudice has 

 to be got rid of before either of these 

 machines can be brought into general 

 use; and before the second Crystal 

 Palace is finished, we shall see mechani- 

 cal power applied to such purposes to a 

 much greater extent than has as yet even 

 been anticipated. 



For Read's, Stevenson's, Saul's, Paxton's, 

 &c, sash-bars to prevent drip, vide article 

 Glass and Glazing. 



§ 4. — WALL-PLATES. 



These are of wood, cast-iron, or stone : 

 the two latter are much to be preferred, 

 on account of their greater durability. 

 The former has hitherto been most gene- 

 rally used, no doubt from the circum- 

 stance of hothouses being for long con- 

 structed entirely of this material. From 

 their position, wall-plates are much 



