Alfred Marshall Mayer

“ The simplicity and precision of the author's experimental methods, his conscientiousness in being sure of one step before he takes the next, and the skill displayed in interpreting and combining his experimental results—all these admirable characteristics have rendered his book instructive and entertaining to those who merely follow from afar the progress of science, while, at the same time, he has furnished a model of precise research and clear exposition to the professed scientist. ”

“ Yet it has been said that Henry was not a man of genius. As I have not been able to find that the philosophers, who have the special charge of giving from time to time definitions of genius, have been able to come to any satisfactory conclusion among themselves, I will leave their company, and, with your liberty, take my definition from a book which, if we accredit Thackeray, is one of the very best, if not the best, novel ever writ in English. ”

“ The explanation of this phenomenon appears to me to be as follows: a wing, or any surface whatever, which moves against the air, meets, at the beginning of its motion, a considerable resistance, on account of the inertia of the air, which resists every displacement; but, little by little, the air yields, and the velocity of its motion gradually increases, until it may equal that of the moving surface which displaces it; this phase of motion having been reached, the resistance diminishes. ”

“ I say efficient and wise, because these two characteristics are not always united in the same person. Indeed, most of the inefficiency of the world is due to their separation: wisdom may know what ought to be done, but it requires the aid of efficiency to accomplish the desired object. I hope that in the education of your son due attention may not only be given to the proper development of both these faculties, but also that they will be cultivated in the order of nature: that is, doing before thinking; art before science. ”

“ One who has never made a special investigation of the character of the impressions on the phonograph, and forms his opinion from their appearance to his eye, might state that they are simply dots and dashes, like the marks on the filet of a Morse instrument. ”

“ When a body moves in a straight line, with variable velocities at each instant, it is easy to obtain the graphic representation of its motion, provided the space moved over is not too extensive. It suffices to join the body, by means of a rigid connection, with a writing-lever, which touches a revolving cylinder, covered with smoked paper. The tracer on the writing-lever, moved with variable velocities, and in a direction parallel to the axis of the cylinder, will draw sinuous curves, whose parts will indicate by their inclination the velocities of the motions which produced them. ”

“ Finally, when the wing has reached the lowest point of its depression, it is not over the mass of air which it has just set in motion, because the motion of translation of the bird continually brings it into regions where the air is at rest. All of these conditions are evidently favorable to flight, since they increase the resistance of the air, which alone furnishes to the bird its support, and the reaction to its moving wing. ”

“ The mind of the reader does not rest on the fallible judgment or mere opinion of the author, but is brought face to face with the very records made by the phenomena themselves.
In studying the progress of science, one cannot help remarking certain periods of sudden acceleration in the progress of discovery. ”

“ Of course an elevation of the membrane in the first drum will cause a depression in the membrane of the second drum, accompanied by a movement of the lever opposite to that described above. Thus the lever records accurately every movement of the membrane of the distant drum, and the intervening flexible tube allows one to attach the drum to the limb of a moving man, or quadruped, to the wing of a flying-bird, or to the chest, to obtain the traces of the motions of the lungs and of the heart. ”

“ It is necessary to give to the cylinder a very regular motion of rotation while it receives and reproduces the vibrations made in singing; for even slight irregularities in the velocity of the cylinder destroy the accuracy of the musical intervals, and cause the phonograph to sing falsetto. Even the reproducing of speech is greatly improved by rotating the cylinder by mechanism which gives it uniformity of motion. If you make the machine talk by giving it a more rapid rotation than it had when you spoke to it, the pitch of its voice is raised ”

“ Leaving out of consideration the inventions which are evidently defective, we have thought it possible to divide the majority of the systems of artificial flight into helicopterons, areoplanes, and orthopterons (from ὸρθός, straight, and πτερόν, a wing) . The helicopterons sustain themselves by the aid of screws whose axes of rotation are nearly vertical. They may be made to progress either by these vertical screws or by special screw-propellers. The areoplanes have propelling surfaces which are nearly plane and slightly inclined to the horizon. ”

“ To Marey we are indebted for many effective recording instruments, but the apparatus which he has most extensively used, and which is admirably adapted to the study of the motions in some of the vital functions and in locomotion, consists of a small drum of shallow depth, one of whose ends is covered with an elastic membrane. The interior of this drum is connected with the interior of a similar drum by a rubber tube of very small internal diameter. The membrane of one of these drums presses against the surface whose motions we would study. ”

“ According to our view there is a sharp distinction to be made between hovering and the ordinary flight of progression, while the amplitude of the changes in the plane of the extremity of the wing is essentially a function of the velocity of translation of the bird. ”

“ If we attach to the foot of a walker a thread, which is wrapped around the wheel on the first axle of the wheel-work, and if to the third axle we connect the writing-lever, we can obtain traces on the revolving cylinder which will have only 1/100th of the extent of the paths gone over by the foot of the walker.
Fig. 1 shows five traces obtained from the foot when walking with various velocities. A has been produced by the slowest walk; "B" is the ordinary gait; while C is the most rapid: the remaining traces have been obtained from gaits less rapid than that of C. ”

“ Experiments made in precisely the same conditions sometimes present slight differences, which are due to the fact that the slightest oscillation of the iron wire, which serves as a support and guide for the artificial bird, slightly changes the durations of the phenomena. From the first series of experiments, it would appear that the duration of the depression of the wing increases in proportion to the velocity of its translation, at least within the limits of the velocities with which I have experimented. ”

“ But, in considering the difficulty of the construction of our mechanical bird, we were obliged, notwithstanding our desire to make a machine which should be simple and easy to understand, to try to perfect those actions we have somewhat summarily described. It is evident that the different parts of the wing, from its base to its extremity, act on the air under very different conditions. The interior part of the wing, having small velocity, produces little propelling effect at any moment of its beat ”

“ He is of the opinion that the outer portion of the wing in ascending exerts always a propulsive action, and he attributes to the propelling parts and to the sustaining, kite-like parts of the wing, proportions which are relatively the reverse of those to which we have been led by our calculation.
It was with these ideas, favorably judged of by the Academy in September, 1871, that we undertook the application of the torsion of caoutchouc to the problem of the mechanical bird. The wings of our bird are made to beat in the same plane by means of a crank and connecting rods. ”

“ The plane of the wing at its base varies but little during flight; the plane of the median part of the wing is very much displaced on one and the other side of its mean position; finally, the outer part of the wing, and especially its tip, experiences considerable change of plane. This warping of the wing is modified at each instant during its elevation and depression, in the manner just indicated; at the extreme points of its beat the wing is nearly plane. ”

“ If gravity does not alone act in producing the oscillation of the leg, it becomes impossible to foresee what motion will result from its combination with muscular action. I have appealed to the graphic method for the experimental answer to this question. ”

“ NUMEROUS attempts have been made at different times to construct a machine capable of propelling itself through the air. All kinds of aërial propellers have in turn been tried; such as screws, beating wings, umbrellas which open and shut during their reciprocating motion, inclined planes, aërial wheels. ”

“ Concerning each of which, many seem to have fallen into very great errors; for by invention, I believe, is generally understood a creative faculty, which would indeed prove most romance writers to have the highest pretensions to it; whereas by invention is meant no more (and so the word signifies) than discovery or finding out ”

“ For example, if the compound sound is formed of six harmonics, the removal of the source of the sonorous vibrations, from the membrane to a distance equal to 14 of a wave-length of the 1st harmonic, will remove the 2d, 3d, 4th, 5th, and 6th harmonics to distances from the membrane equal respectively to 12, 34, 1, 114, and 112 wave-lengths. ”

“ In fact, on observing the superposition of the different parts of these curves with the curve of translation, we see that the body receives an increase of velocity about the middle of the period when either foot is on the ground. ”

“ The permanent impressions of the vibrations of the voice are now made. It remains to obtain from these impressions the aerial vibrations which made them. Nothing is simpler. The plate A, with its point, P, is moved away from the cylinder by pulling toward you the lever H G. Then the motion of the cylinder is reversed till you have brought opposite to the point P the beginning of the series of impressions which it has made on the foil. Now bring the point up ”

“ These two ruling qualities, clearness and conciseness, become every day more desirable, by reason of the enormous increase in biological publications." In his last work, "Animal Mechanism," be has illustrated this remark; for surely no "tediousness" will be experienced in the perusal of this work, in which we are taught, with such "clearness and conciseness," how men and quadrupeds walk and run, and how birds and insects fly. ”

“ He was a diligent student of mental philosophy, and also took a lively interest in the progress of biological science, especially in following the recent generalizations of Darwin, while the astonishing development of modern research in tracking the history of prehistoric man had for him a peculiar fascination. ”

“ Wood, whalebone, and steel, give forces which are at a minimum when referred to their weight; caoutchouc is much more powerful, but the framework necessary to resist its violent tension is necessarily quite heavy. ”

“ He then succeeded in giving sustained flight to his machine, which we have ourselves seen fly horizontally nearly seven metres, after having been started by a slight impulse from the hand. M. Tatin, also, in 1874, made two very curious artificial birds, using twisted caoutchouc as a motor. M. Marey has told us that he saw the first named fly in his garden, last November, from eight to ten metres. We have seen the second, nearly identical with our bird, fly in a still more satisfactory manner. ”

“ Finally, each loved science more than money, and his Creator more than either.
There was sympathy between these men, and Henry loved to dwell on the hours that he and Bache had spent in Faraday's society. I shall never forget Henry's account of his visit to King's College, London, where Faraday, Wheatstone, Daniell and he had met to try and evolve the electric spark from the thermopile. Each in turn attempted it and failed. Then came Henry's turn. He succeeded ”

“ Finally, in the orthopterons, the propelling organs are surfaces moving in vertical directions, and generally having reciprocating motions. In this system are embraced the wings of birds and the moving surfaces of the tails of fishes. ”