POPULAR MISCELLANY 



5 1 



more complex problems, as will be seen 

 from the following account of their labors, 

 which we take from the English Mechanic. 

 In these experiments by pressure of a brush 

 saturated with a concentrated solution of 

 a savory substance on the tongue, an elec- 

 tric circuit was closed, which was only 

 opened by the person when he made a sig- 

 nal "on first perceiving the taste. The time 

 during which the current flowed was marked 

 by a rotating cylinder, and represented the 

 ''reaction-time" of a given taste. First, 

 the " reaction-time " of four different sub- 

 stances was ascertained. This experiment 

 was then so modified that not merely the 

 sensation of taste had to be answered to, 

 but the tongue of the person was touched 

 now with water, now with a savory solution, 

 without his knowing beforehand which was 

 to be applied ; he had to decide which had 

 touched his tongue, and gave the signal 

 only when it was the savory matter. In a 

 final series of experiments there were always 

 two savory substances used : when the per- 

 son perceived the one, he gave the signal 

 with one hand; when he perceived the 

 other, with the other hand. Here the per- 

 son had not only to perceive the sensation, 

 but to distinguish the one taste from the 

 other, and then to make the right choice of 

 the hand to give the signal. The results 

 are stated in the table below, where the 

 first vertical series gives the names of the 

 savory substances ; the second, the time in 

 seconds between the application of the sub- 

 stance and giving of the signal ; the third, 

 the reaction-time when the savory substance 

 was applied interchangeably with water, and 

 must be distinguished from this ; the fourth, 

 fifth, sixth, and seventh, the reaction-time in 

 comparison with common salt, acid, sugar, 

 and quinine, respectively : 



SUB- 

 STANCES 



Simplt 

 Sensa- 

 tion. 



COMPAKISON WITH 



Water. 



ComnVn 



salt... 0.1 oils 0.2700 

 Acid.... 0. 1070 0.3315 



Salt. 



0.3749 



Acid. 



0.3338 



Sugar. 



Quinine 



0.3378 0.4S04 

 0.40S1|0. 401)0 



Si'v'-ir' ' ' 611639 6'.3840 0.3GS8 0.4373 0.4224 



Quinine' 0.2196 0.4129 0.4888 0.5095, 0.4210| 



" If we take as a basis," say the authors, 

 " the reaction-times when the tongue was 

 touched with a savory substance alone, and 

 compare therewith the reaction-times which 

 were obtained in the experiments whether 



with water, or with another savory sub- 

 stance, we find that the following law gen- 

 erally holds : If we experiment with distilled 

 water and a savory substance, or inter- 

 changeably with two savory substances on 

 the tongue-tip, then the time of recognition 

 of the one (in experiments with water), or 

 of the two (in experiments with savory sub- 

 stances), is longer, the longer the reaction- 

 time of one of the savory substances on sim- 

 ple application." The converse of this law, 

 however (which is only in general valid), 

 does not hold good. 



An Underground Pnenmatie (lock-Reg- 

 ulator. The inhabitants of modern cities 

 who are accustomed to receive their sup- 

 ply of water and illuminating gas through 

 pipes laid under the streets, and who are 

 prepared to welcome the introduction of 

 a system of steam -heating on a large 

 scale, will next "get the time of day" 

 from underground pipes. A plan of reg- 

 ulating clocks by means of compressed 

 air has been devised by an Austrian en- 

 gineer named Mayrhofer. Its principle 

 will be understood from the following de- 

 scription, which we take from the Boston 

 Journal of Chemistry : In the first place, 

 tubes are laid to convey compressed air from 

 a central station, in which is the " master- 

 clock." A simple contrivance, connected 

 with the tubes and the clock, lets off a puff 

 of air every minute or half-minute, and the 

 fingers of all the clocks in the system are in 

 that manner pushed forward with unerring 

 accuracy, in accordance with the time indi- 

 cated by the standard timepieces in the 

 observatory, so that exact uniformity can 

 be maintained without difficulty in the time 

 shown on any number of dials. The weather 

 has no effect on the air, so far as the work- 

 ing of the pneumatic clocks is concerned, 

 and, be it hot or be it cold, the little valve 

 lets off its puff of air, and the clocks go 

 accurately, in defiance of atmospherical in- 

 fluences. A small yearly charge is made 

 for the clocks, and there is no further ex- 

 pense or trouble. The system has been in 

 operation in Vienna for nearly four months, 

 and has worked without a solitary hitch, so 

 that the people are beginning to realize the 

 idea that time can be " laid on " in then- 

 houses as readily as either water or gas. 



