4-12 



SCIENCE. 



[Vol. XIV. No. 358 



— " ' Evolution of Sound ' Evolved " is a review of the article 

 ■entitled " The Nature of Sound," in " The Problem of Human 

 Life," by Marcellus Thompson, professor of natural sciences in 

 ■Garfield University, Wichita, Kan. To this work is appended an 

 account of some original experiments in electricity which Professor 

 Thompson conducted when a candidate for the master's degree at 

 -the University of Michigan. This work has been warmly received, 

 as witness testimonials from John W. Langley, professor of 

 •general chemistry in the University of Michigan ; Alfred Fairhurst, 

 professor of natural sciences in Kentucky University ; B. J. Rad- 

 ford, associate editor of the Christian Standard ; John B. De 

 "Motte, professor of physics in DePauw University ; O. P. Hay, 

 professor of biology in Butler University ; David S. Jordan, presi- 

 -dent of Indiana State University; A. E. Dolbear, professor of 

 physics in Tufts College ; C. Williams Parks, professor of physics 

 -in Rensselaer Polytechnic Institute. 



LETTERS TO THE EDITOR. 



'^^*CorresJ>ondents arerequestedtobe asbrie/ as possible. The writer's name is 

 ■in allcases required as proof of g^ood faith. 



The editor will be glad to publish any queries consonant with the character of 

 -the journal. 



On request^ twenty copies of the nutnber containing his communication will be 

 .furnished free to any correspondent. 



A Belated Dandelion. 



The day before Thanksgiving I found in full bloom a fine dan- 

 delion-head measuring one and one-half inches in diameter; yet 

 the record of temperatures for the November just past shows a 

 lower average than that of any November in Kansas since 1880. 



E. B. KNtRR. 

 Atchison, Kan., Dec. s. 



Is Man Left-Legged ? 



Last Sunday, while walking on the beach at Nahant, we tried 

 -some experiments bearing on the subject. We found that, walk- 

 ing either forward or backward with the eyes shut, we bore to the 

 right, but in running either forward or backward we bore to the 

 ■left. This last fact surprised us somewhat at first ; but we thought 

 it might be explained from the fact that, the left leg being the 



■ stronger, there would be a stronger spring from the left foot in 

 running, which would make the right leg take the longer step. 

 We should be glad to hear if others have tried these experiments, 



■ whether with the same or different results. 



Fred'k a. Lovejoy. 

 Francis H. Allen. 



West Roxbury, Mass., Dec. 8. 



INDUSTRIAL NOTES. 

 The Crocker-Wheeler Electric Motor. 



The Crocker-Wheeler Electric Motor Company of this city are 

 ■now putting on the market a series of electric motors which show 

 -a considerable advance in design, construction, and efficiency. 

 Two of their smaller motors are shown in the illustrations on this 

 -j)age. Fig. i shows a i-horse-power motor belted to a small three- 

 piston suction and force pump, which is capable of lifting a thou- 

 sand gallons of water per day a height of a hundred feet, and other 

 quantities a correspondingly greater or less height. When desired, 

 the motor is connected to the pump by toothed or friction gearing 

 instead of by a belt. 



By means of an automatic attachment to the ordinary float in 

 the water-tank, the electric current is cut off from the motor when 

 the tank is full, thus stopping the pump until enough water has 

 Tseen used from the tank to allow the float to fall, thus starting the 

 motor and pump again by switching on the electric current. This 

 •cycle of operations being entirely automatic, the water-supply is 

 never exhausted, and no more electric energy is absorbed than is 

 just sufficient to pump enough water to supply the demand. 



Fig. 2 shows one of the new Crocker-Wheeler arc motors with 

 fan, and a regulator which effects any desired change in the speed 

 -and power of the machine by simply moving the armature out of 



the field. By this simple device the necessity of a switch, com- 

 plicated windings, and attendant evils are entirely overcome. 



The motors are built of very few pieces, and are strong and 

 durable. They are designed with a broad base and a low centre 

 of gravity, in order to render them perfectly steady and quiet in 

 their operation. In their care they require a minimum of attend- 



FIG. I. —NEW C.-W. ELECTRIC PUMP. 



ance. They are arranged to be controlled by either of three 

 methods of regulation, — for constant load, for variable speed, and 

 for constant speed, — any one of which is obtained by attaching 

 the corresponding regulating fixture. 



The motors are arranged so that they can be reversed by simply 

 inverting the brush-holders upon the clamping-rods, so that the 

 upper brushes are placed below, and the lower ones above. By 



FIG 2 — NEW C.-W ELECTRIC FAN 



this device the machines can be run either right-handed or left- 

 handed without taking apart or changing any connections. They 

 are wound for every kind of circuit, and those of different windings 

 are always compared to see if the same efficiency and proportion of 

 ampere-turns are maintained. On the smallest size, about 2,500 

 ampere-turns are used to magnetize the field, the total loss in the 

 machine due to resistance never being permitted to exceed about 

 47 watts. 



