BAR 



BAR 



30 . 



24 



10. 



and pieces, B, acting as spurs, framed 

 into the poles. The roof is light and 

 covered with thatch. At each angle 

 is a strong block of wood, with a 

 round hole in it, sufficient to let the 

 poles pass through ; these blocks are 

 kept at any desired height by means 

 of iron pins passed through' holes 

 made in the poles, and on which the 

 blocks rest. To raise the roof, a 

 small jack is used, an instrument well 

 known by its use in raising heavy 

 wagons when the wheels are taken 

 oft'. This is placed on an iron pin at 

 some distance below the roof, and the 

 corners are raised gradually, one after 

 the other, at opposite angles, the pins 

 being moved each time one hole high- 

 er. The chief use of this Dutch barn 

 is to contain hay, which may be pla- 

 ced in safety, in any small quantity, 

 as soon as made, the roof being raised 

 as the quantity increases, and grad- 

 ually lowered as it is taken off for the 

 cattle, which is always from the top. 

 In small dairy farms in Holland, this 

 building is found so useful that few 

 68 



are without one. Four posts are 

 quite enough. 



BARN OWL. This bird is a val- 

 uable destroyer of rats, mice, and 

 small vermin. 



BAROMETER. Of all the mete- 

 orological instruments the barometer 

 is the most useful to the cultivator. 

 Although its principal object is to in- 

 dicate the pressure of a column of air, 

 the variations of this same pressure 

 are so intimately connected with di- 

 vers other atmospheric phenomena, 

 that one can almost dailj" recur to its 

 indications with profit. 



The barometer in its simplest form 

 is a tube curved into a siphon {Fig. 1 ), 

 closed at the upper end, Miih a pear- 

 shaped enlargement at the lower end, 

 completely void of air, and partly fill- 

 ed with mercury. When the tube is 

 placed in a perpendicular position, the 

 metal, after some oscillations, settles 

 itself at a height which represents the 

 weight of the atmosphere, and which 

 varies more or less, according as that 

 weight augments or diminishea 



