ORIGIN OF THE CRYSTAL PALACE. 195 



when the weight or " thrust " of the roof tends to force them 

 apart. 



In some buildings, such as an old country church which I 

 attended for many years, the architect had openly acknow- 

 ledged the tendency of the walls to fall outward, and had 

 counteracted it by a series of great beams extending com- 

 pletely across the nave and aisle. As he had not even troubled 

 himself to hide their office, so he did not trouble himself to 

 conceal the fact that they were tree-trunks, but left them 

 roughly squared with the axe, lest, if he had squared them 

 throughout their length, he should have diminished their 

 strength. 



The effect of the partially squared beam is, of course, far 

 more picturesque than that of a completely squared one. The 

 architect, however, need not have been so careful about strength, 

 for if the beams had been only half their diameter they would 

 have been just as effective. The strain on them is by pulling, 

 and not by pushing. Now, as any one can see by trying the 

 experiment with a splinter of wood — say a lucifer-match — an 

 enormous power is required to break it by tearing the ends 

 asunder, while it can be easily broken by pushing them towards 

 each other. 



But for this power of resistance, we should never have had 

 our Crystal Palace. That apparently intricate, but really 

 simple (and the more beautiful for its simplicity), intersection 

 of beams and lines diminishing in the distance to the thick- 

 ness of spiders' webs, is nothing more than a combination of 

 the Girder and Tie, the two together combining lightness and 

 strength in a marvellous manner. 



The story of the Crystal Palace is now so well known that it 

 need not be repeated in detail. A vast building was required for 

 the Exhibition of 1851, and not an architect was able to supply 

 a plan which did not exhibit some defect which would make 

 the building almost useless. 



Suddenly a Mr. Paxton, who was a gardener, and not an 

 architect, produced (on a sheet of blotting-paper) a rough plan 

 of a building on a totally new principle, and not only fulfilling 

 ail the requisite conditions, but being capable of extension in 

 any direction and to any amount. There have been very few 

 bolder conceptions than that of making iron and glass take the 



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