REACTIONS OF ANIMALS. 



The untreated air entered the final delivery pipe after passing through a '.glass 

 wool filter. The wet air passed from the glass wool filter through two 2-liter\ as- 

 pirator bottles filled with crushed pumice impregnated with distilled water. /To 

 test the evaporating power of the three kinds of air, Livingston ('06, '08, 'ioa, 'iob, 

 'n ; see Abbe, '08) cup atmometers (evaporimeters) were used. Small Whitehall 

 Tatum museum jars, similar to those used for the sulphuric acid filters, 19 cm. 

 deep inside, and 9 cm. in diameter at the neck, were used to confine the atmom- 

 eters. The atmometers were placed in position, after being stoppered with one- 

 holed rubber stoppers with small tubes inserted. A large stopper with three holes 

 was used to carry all the apparatus inside the jar. The tubes which connected 

 them with burettes, where the amount of water evaporated was read off, passed 

 through the central hole of the large stopper. Another tube which connected with 

 the air supply passed through one of the side holes, parallel with the evaporimeter 

 and reached within about 5 mm. of the bottom of the jar. The apices of the 

 evaporimeter cups were from 25-30 mm. from the bottom. The third hole in the 

 stopper was used for the exit pipe; the air from the supply passed upward to the 

 bottom of the jar, which was inverted, and in returning to the exit tube, passed 

 over the atmometer. The size of the jar was such that the velocity of the air 

 over the atmometers was the same for a given flow, as across the cages. An 

 atmometer thus enclosed was provided for each of the three kinds of air. For 

 testing relative humidity (Fig. iC), two long chemical thermometers, graduated 

 to o.i of a degree, were inserted inside of a glass tube 50 cm. long and 22 mm. in 

 diameter. One of the thermometers was provided with a wick of absorbent cotton 

 toweling, which dipped into a vial of water. Air from a supply pipe could be 

 introduced into the tube below the bulbs. 



Two glass Y's were inserted between the filters and the experimental box, in 

 each air line. The respective stems of these connected with the main air tube 

 and with the experimental cage, as indicated in Fig. i . One arm of the Y of each 

 line was connected permanently with one arm of the Y attached to the experi- 

 mental box and supplied with a pinch-cock. The six free Y arms were supplied 

 with free rubber tubes as shown in Fig. i. The three of these connected with 

 the nearest filters could be joined to the observations tubes (Fig. i), or to the 

 atmometers, or the thermometer tube. The other three (FT) could be used to 

 connect the experimental cages directly with T of the control tube to give a rapid 

 flow or when a coil of aluminum pipe submerged in hot water was interposed, to 

 give warm air. These six free tubes made possible cross connections and the shift- 

 ing of any kind of air to any section of the experimental cage. All open tubes 

 were closed by means of pinch-cocks. 



For studying details of behavior and testing the ability of the animals to with- 

 stand high rates of evaporation, three glass tubes, each with a total length of 21 

 cm. and an inside diameter of 32 mm., were used. These were connected with 

 the free rubber tubing of the less frequently used arms of the Y's by means of 

 funnels of the same diameter as the inside of the tubes. The stems of these were 

 inserted into single-holed rubber stoppers. The large end of the funnel was cov- 

 ered with a screen whose meshes were i mm. square, and the whole inserted inside 

 the tube, with the stem projecting outside the rubber stopper for the attachment of 

 the rubber tube. The funnel permitted the expansion of the air so as to practically 

 fill the tube when it entered, and the screen prevented the small insects from entering 

 the rubber hose. The air left each tube through the small funnel, similarly inserted 

 into the other end. Since animals find difficulty in walking on curved glass sur- 



