22 Trans. Acad. Sci. of St. Louis. 



similar tube at right angles to the former, and forming 

 the arms of a T. From the ends of these arms short tubes 

 return to the wall of the building, and serve as feet for hold- 

 ing the conducting tube in position, when it is pulled into 

 position from within. The ends of the feet should be plugged, 

 and one of them should be adjustable, to provide for inequal- 

 ities in the wall surface. The end of one arm of the T should 

 also be closed. From the other, a tube extends six or eight 

 inches, and an elbow and tube return towards the building 

 and carry the pressure collector. The plane of the collector 

 is parallel to the surface of the wall, and should be one or 

 two inches from it. Collectors should be placed over the 

 various walls of the building and upon its roof. The tubes 

 should be adjusted to the same resistance, and as nearly as 

 possible, to the same capacity, so that all will respond with 

 equal quickness. The gauge tubes should be parallel and side 

 by side, so that they may be photographed at any instant, when 

 a heavy gust of wind is blowing. The gauge tubes should of 

 course lead into a tank, connecting by a large tube with a 

 large Abbe collector above the roof. This collector should 

 be high enough above the roof to escape the effect of the 

 building. The stream lines should be horizontal where this 

 collector is placed. Near the summit of inclined roofs, ou 

 the windward side, and over the entire leeward side, the 

 pressure is reduced by a wind. On a, flat roof the pressure 

 is always reduced. The pressure is less than that of the 

 atmosphere, and this reduction of pressure increases with an 

 increase in velocity. The standard pressure should be col- 

 lected from a point above these disturbances. 



When the wind blows at right angles to one side of a build- 

 ing, the pressure on all other sides is diminished. If a win- 

 dow yields on the windward side the pressure within the 

 house will be increased. The tendency is to lift off the roof, 

 and throw three walls outwards. The windward wall is often 

 braced by partitions so that it is less likely to fall in than 

 the others are to fall out. I believe that it is possible to 

 greatly increase the resisting power of ordinary farm build- 

 ings against wind without materially increasing their cost. 



