Experiments of this sort were discontinued in the summer. In October I tried No. 1 with the right and left hand experiment, he being in a new room and cage, and I being seated in a different situation. He came down at both signals and failed to make any ascertainable progress with the no signal in 80 trials. (October 20-24.) [Illustration: FIG. 30.] I then tried him with the black and buff diamonds, the black being in front (October 25-29). The reaction to the ‘yes’ signal was perfect from the start. The progress with the ‘no’ signal is shown in Fig. 30, _d_. I then tried him with an apparatus externally of different size, shape and color from that so far used, showing as the ‘yes’ signal a brown card and as the ‘no’ signal a white and gold card one half inch farther back in the apparatus. The ‘yes’ signal was practically perfect from the start. His progress with the ‘no’ signal is shown in Fig. 30, _e_. I then tried a still different arrangement for exposure, to which, however, he did not give uniform attention. I then tried cards 1 and 101, 101 being in front and 1 in back. 1 was the ‘yes’ signal. ‘Yes’ responses were perfect from the start. For ‘no’ responses see Fig. 30, _f_. I then put the ‘yes’ signal in front and the ‘no’ signal behind. ‘Yes’ responses perfect; for ‘no’ responses see Fig. 30, _f_, _a_. From now on I arranged the exposures in such a way that there was no difference between the ‘yes’ and ‘no’ signals in distance or surroundings. The following list shows the dates, signals used, and the figures on page 199 presenting the results. Where there is only one figure drawn, it refers to progress with the ‘no’ signal, the ‘yes’ signal being practically perfect from the start. TABLE 10 ==================+==============+=============+======== | ‘YES’ SIGNAL | ‘NO’ SIGNAL | FIGURE ------------------+--------------+-------------+-------- Nov. 13-15, 1900. | 2 | 102 | _g g₁_ Nov. 14-16, 1900. | 3 | 103 | _i i₁_ Nov. 16-19, 1900. | 4 | 104 | _h_ Nov. 19, 1900. | 5 | 105 | _j_ Nov. 20, 1900. | 6 | 106 | _k_ Nov. 21, 1900. | 7 | 107 | _l_ Nov. 23(?), 1900. | 8 | 108 | _m_ Nov. 27-29, 1900. | 9 | 109 | _n_ Nov. 30, 1900. | 10 | 110 | _o_ ==================+==============+=============+======== Fig. 29 gives facsimiles of the different signals reduced to one sixth their actual size. The drawing of 101 is not accurate, the outer ring being too thick. EXPERIMENTS WITH NO. 2 [Illustration: FIG. 31.]