The horizontal sha^b has nt either end a conical gear which 

 in turn engages anotb.er conical gear v/ith three times as :nany 

 teeth and which is fastened to q vertical shaft supported and 

 steadied by a tripod. Lt its free end this last-named shaft 

 carries two paddles pointing in opposite directions, each 1«25 

 meter long and tapering in width from 0«25*m» to 0.15 n. The 

 sidev/ay pitch of each paddle is adjustable. 



The ratio of 1:3 between the conical gears allows for a 

 speed of about 8 RPM for the vertical shaft? and thus for the 

 paddles e The disturbance of the water is further influenced by 

 changing the, pit.ch of the aforementioned paddles. 



In'- fig-ujre .seven these paddles nay be seen through the water 

 in the tank*.' The tanks have a capacity of about 3»5 j: 3«5 x 1,2 

 cubic meters and the sides extend some 10 cm. above the v/ater 

 surface. This however proved to be insufficient because of vmve 

 action which '«Tas common at o^or site so that later the tank vralls 

 were built up another 15 cn« higher. Outside vrater must obviously 

 not be permitted to enter the tanl:s over the side since weeds, 

 fish anjd obher marine animals are also apt to intrude. 



The vj-allS' of the tanlcs vrare made of wood impregnated v/ith 

 carbolinevin (creosote?) and tarred. The seams between tir.it'ers and 

 boards were not calked, a neglect v/hich led to difficulties since 

 upon cleaning the tanks the seams proved to be hiding places for 

 all manner of lobster-like rnimals like crrbs, Gamjiiarus, %siden, 

 etc., iThich were hard to dislodge. Although the food of these 

 aninr.ls vdll nn doubt have consisted mostly of refuse it is not 

 impossible that they did absorb lobster larvae also. Considering 

 the great nvmber present the damage they did was perhaps not 

 uninpressivee 



To provide a change of vrc'.ter in the tanlcs, openings yrere cut 

 in each of two sidewalls and in the bottom. These openings, one 

 of 100 X 20 cut in each sidevall and two of 50 x 50 cm. in the 

 floor were cover e-" with copper screening of a 1,6 m:Ti, nesh fastened 

 on the inside witli a narrovr v/ooden framing. 



For the purposq of hoisting the tanks for cleaning and reprir- 

 ing a removable tripo-- and tackle \Tere provided. Kcwever a diff- 

 erent arrangement later proved to be more efficient. 



Acquiring thp m.otor in 1919 wr s very difficult. The siipply of 

 light gasoline motors suitr'.blo for our purpose v^rs practically 

 exhausted and prices very hi;^h. Finally it v/as decided to buy a 

 1-g- hp vertical motor (Premier) v/hile an Evinrude outboard motor 

 T;as converted to a stationary t;/pe as a reserve engine* 



The groat drawback of both motors was thrt they operated 

 through ignition provided bj'" a battery. Various circumstances. 



129 



