254 Mr Hope on Wood Paving. 



It appears that the amount of wear is greatest in the first 

 month, and gradually decreases every subsequent month. 

 For instance, the wear for the first and second months is 

 greater than any three months from the sixth. This, I think, 

 can be very satisfactorily accounted for. Although the depth 

 of the blocks diminished more in proportion for the first and 

 second months, yet they did not seem to have lost much by 

 abrasion. They had undergone compression, and presented 

 a more compact surface than when laid down ; and, besides, 

 being more compact in fibre, the surface was so impregnated 

 with fine sand, that it had more the appearance of stone than 

 wood. 



1. The vertical fibre blocks during the eighteen months 

 were only diminished in depth, between compression and abra- 

 sion, .125, or ^th of an inch. The blocks at the end of that 

 time were in as good condition as if they had not been ex- 

 posed to heavy weights and abrasion. 



2. The blocks with the fibres leaning at an angle of 75 de- 

 grees, shewed the additional wear of .022 at the end of the 

 eighteen months, which is the 40th part of an inch more than 

 if they had been vertical. The surface shewed a greater abra- 

 sion of the soft fibres, and the resinous fibres were slightly 

 pressed to the leaning side. 



3. The next are those with the fibres at 60 degrees. At 

 the end of the first month, the diminution in depth was .032, 

 nearly double that of vertical ; and at the end of the eighteen 

 months they were diminished .182, which is about ^^ths of an 

 inch ; clearly shewing that blocks at that angle must lose ^^^th 

 of an inch more than vertical blocks. The surface was not 

 so regular as the preceding, occasioned by the larger circles 

 of soft fibre sustaining greater abrasion, and these as well as 

 the smaller circles being unable to resist so much pressure at 

 that angle, were so squeezed as to lose their cohesion on the 

 immediate surface ; and the resinous fibres being also unable 

 to resist pressure at that angle, instead of protecting the 

 softer, were leaning on them, and to a small extent shewed a 

 tendency to separate into threads. 



4. The blocks with the fibres leaning at 45 degrees, lost ra- 

 ther more at the end of one month than the vertical did at 



