stai;le construction and fittings. 49 



answer as well as any other device, and the multiphcation of 

 grooves makes cleaning difficult. There is probably no 

 vitrified brick which does not wear somewhat slippery, but on 

 the whole they make the best paving. 



(3) Sto?ie slabs wear smooth and require constant re-chipping ; they 



also become cracked a good deal and cannot be called a good 

 flooring. 



(4) Granite setts wear for a very long time, but want re-chipping 



frequently as they get smooth, and they never give a quite level 

 standing. 



(5) Concrete is laid in several varieties, some of which are good, 



durable and non-slipping : but other samples are the reverse 

 and require continual chipping to make them at all safe. 



(6) Asphalt is too easily affected by heat, and gets too slippery when 

 wet to make a satisfactory stable paving, and especially is this 

 the case when calkins are worn. 



(7) Wood blocks or any other materials which will absorb wet are 

 quite unsuitable, although when treated with creosote the former 

 may be very usefully employed in forges and outbuildings. 



Dimensions of stalls. — The dimensions laid down for the construction of Dimen- 

 stable blocks are : — Normal breadth of block, with one row of stalls, sions ot 

 18 ft., with two rows, 31 ft. Height sufficient to give not less than ^'^^'^^• 

 1,500 cubic feet per horse. All stalls against external walls. Stalls 

 5 ft. 6 in. wide, centre to centre, and 1 1 ft. long from wall to centre of 

 heel post. Crib-biter stalls 6 ft. in the clear between walls. 



Ventilation. 



The subject of ventilation is best studied here so that its bearing on 

 the cubic space necessary may be fully appreciated. The object of 

 ventilation is to change the air of a building frequently enough to keep 

 it pure without allowing a draught to strike the occupants. Fresh air is Composi- 

 approximately composed of — *^^°" °^ ^^^* 



Oxygen 2,099 



Nitrogen 7)899 



Carbonic acid ... 2 



per 10,000 volumes. 

 (b 10948) 



