explanatio:n" of plates. 



Plate 1. 



General view of houseboat with floats attached — looking forward. The ends 

 of the pontoons show 1 and 2. On the after deck is one of the large propellers. 

 The shaft is seen coming through the side of the engine house and running out 

 over the floats. The general relation of the rearing cars, alleyway, and barrels 

 is seen in the right-hand floats. On the left, one of the cars is raised for cleaning. 

 In the distance is the houseboat "Biophore," and beyond is the Wickford Light. 



Plate 2. 



Floats from outer corner, looking forward and toward houseboat. The appear- 

 ance of the car in the water and the gearing of the propeller shafts are clearly 

 shown in the nearest car. The blades of the propeller show faintly through the 

 water. 



Plate 3. 



Inside the box, toward one corner. The rippling of the surface of the water is 

 due to the current created by the propeller blades. The gearing immediately 

 connected with the propeller shaft is clearly seen. It consists of a sleeve coupling 

 for disjointing propeller shaft 1, a lever for throwing shaft out of gear 2, a train 

 of mite red gears for reducing speed of propeller shaft 3, adjustable hangers 4. 

 5 truncated corner of box. 



Plate 4. 



One of the outside floats — car raised. The size and the shape of the propeller 

 is well shown. The upper blade shows the upper side, and the lower one the 

 under side with the iron straps holding blades to gaspipe. The vertical shaft of 

 the propeller is shown over the shoulder of the person standing beside the pro- 

 peller. 



Plate 5. 



If the fry have to be transferred, they are scooped out on a flat net of this style 

 and immediately shaken off into a tub of water, thence taken to the car prepared 

 for them. The evidence of the current within the car is well shown here. In the 

 foreground the detail of the portable windlass with its drum and crank appear. 



