4O Horses on Board Ship. 



of the inside currents of air will be to 

 ascend. At the same time we must bear 

 in mind, that the comparatively high specific 

 gravity of carbonic acid gas will tend to 

 cause that gas to accumulate in positions 

 which are low down and ill-ventilated. When 

 the wind is blowing in a direction parallel 

 to the sides of a ship, it will tend to draw 

 air out of all port-holes and freeing ports 

 which are unprovided with air-scoops ; but 

 when it impinges on the side, or when it 

 is directed inwards by an air-scoop, it will 

 naturally tend to force its way into the ship, 

 and will thus convert these openings into 

 inlets. Air-scoops (p. 44) can be utilised 

 with advantage in various ways. 



Hatchways act both as inlets and outlets. 

 Dividing them vertically by means of a 



