xxxii Trans. Acad. Sci. of St. Louis. 



Thus experience determines development and variable responses are 

 accounted for. 



The theory thus given was supplemented by a brief description with 

 lantern slides and sketches of a practical device which operates on 

 something the same principle. The apparatus described is a hydraulic 

 regulating system. The important parts are: 1st, a transmitter or 

 triple slide valve with a timing attachment; 2nd, a measuring or bal- 

 ancing device governing a hydraulic cylinder or motor; 3rd, a system 

 of key rods connected so that each key rod controls one or more trans- 

 mitters and on the other hand each transmitter is controlled by one or 

 more key rods. 



The speaker demonstrated that the apparatus will respond to signals 

 as a nervous system does, i. e., the responses are determined by pre- 

 vious experience. In other words, the speaker showed a practical ar- 

 rangement of valves, pipes, springs, ratchets, cranks, pistons, etc, that 

 will respond to signals and make movements like the nerves and mus- 

 cles in an animal of some intelligence. The mechanism can be trained, 

 can acquire habits, will move forward or back at a given signal, accord- 

 ing to experience, will make one, two or three responses to a given 

 signal, according to experience. 



Professor J. L. Van Ornum spoke on "Experiments 

 on the Pointing of Pressure Tubes, to Eliminate Veloc- 

 ity Effects, in Water Pipes," with especial reference to 

 the auxiliary tubes of Pitometers. 



For a long time it was assumed and still seems to be supposed by 

 aaany, judging from statements in books and periodicals, that the 

 pointing of a pitot tube to give a zero velocity indication when 

 placed in a fluid stream should be at an angle of ninety degrees from 

 the direction of flow; but this is not true. To the members of this 

 Academy the most familiar proof of the fact is contained in paper No. 

 3, of Vol. XVI, of its Transactions, in which Professor Nipher states 

 that a pitot tube in a current of air shows a negative velocity head 

 (when pointed at an angle of ninety degrees from the direction of the 

 air current) greater in amount than the maximum positive velocity 

 head when directly facing the current of air; and that the angle of 

 pointing to show a zero velocity head in air is sixty degrees. 



The thesis experiments of Messrs. Patton and Wallace in the Wash- 

 ington University hydraulic laboratory nearly three years ago and later 

 ones by Mr. Hooper, as well as Dr. Schuster's experiments at Dresden 

 published about two years ago, are definite indications that the same 

 facts are true in currents of water. 



Among the other considerations discussed in the above mentioned 

 theses is one perhaps more important than that just mentioned. It ia 

 the fact that, unless the pitot tubes have the theoretically required per- 

 fectly thin edge, the angle is increased from the sixty degree angle to 

 one of greater size. When a cone, with its base coinciding with the 

 plane of the mouth of the pitot tube, is used, its angle is greater than 



