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pVysiognomy, or in both, to admit of classification ; and I espe- 

 cially desire to show that many methods exist of pursuing the 

 inquiry in a strictly scientific manner, although it has hitherto 

 been too often conducted with extreme laxity. 



The types of character of which I speak are such as those 

 described by Theophrastu?, La Bruyere, and others, or such as 

 may be reid of in ordinary literature and are universally recog- 

 nised as being exceedingly true to nature. There are no worthier 

 professors of this branch of anthropology than the writers of the 

 higher works of fiction, who are ever on the watch to discrimi- 

 nate varieties of character, and who have the art of describing 

 them. It would, I think, be a valuable service to anthropology 

 if some person well versed in literature were to compile a volume 

 of extracts from novels and plays that should illustrate the pre- 

 valent types of human character and temperament. Wtiat, 

 however, I especially wish to point out is, that it has of late 

 years become possible to pursue an inquiry into certain funda- 

 mental qualities of the mind by the aid of exact measurements. 

 Most of you are aware of the recent progress of what has been 

 termed psycho-physics, or the science of subjecting mental pro- 

 cesses to physical measurements and to physical laws. I do not 

 now propose to speak of the laws that have been deduced, such 

 as that which is known by the name of Fechner, and its 

 numerous offshoots, includifigthe law of fatigue, but I will briefly 

 allude to a few instances of measurement of mental processes, 

 merely to recall them to your memory. They will show what I 

 desire to lay stress upon, that the very foundations of the 

 differences between the mental qualities of man and man admit 

 of being gauged by a scale of inches and a clock. 



Take, for example, the rate at which a sensation or a volition 

 travels along the nerves, which has been the subject of numerous 

 beautiful experiments. We now know that it is far from instan- 

 taneous, having indeed no higher velocity than that of a railway 

 express train. This slowness of pace, speaking relatively to the 

 requirements that the nerves have to fulfil, is quite suflicient to 

 account for the fact that very small animals are quicker than 

 very large ones in evading rapid blows, and for the other fact 

 that the eye and the ear are situated in almost all animals in the 

 head, in order that as little time as possible should be lost on 

 the road, in transmitting their impressions to the brain. Now 

 tfie velocity of the complete process of to and fro nerve trans- 

 mission in persons of different temperaments has not been yet 

 ascertained with the desired precision. Such difference as there 

 may be is obviously a fundamental characteristic and one that 

 well deserves careful examination. I may take this opportunity 

 of suggesting a simple inquiry that would throw much light on 

 the degree in which its velocity varies in different persons, and 

 how far it is correlated with temperament and external physical 

 characteristics. Before I describe the inquiry I suggest, ani 

 towards which I have already collected a few data, it is necessary 

 that I should explain the meaning of a term in common use 

 among astronomers, namely, " personal equation." It is a well 

 known fact that different observers make different estimates of 

 the exact moment of the occurrence of any event. There is a 

 common astronomical observation, in which the moment has to 

 be recorded at which a star that is travelling athwart the field of 

 view of a fixed telescope, crosses the fine vertical wire by which 

 that field of view is intersected. In making this observation it 

 is found that some observers are over sanguine and anticipate 

 the event, while others are sluggish and allow the event to pass 

 by before ihey succeed in noting it. This is by no means the 

 effect of inexperience or maladroitness, but it is a persistent 

 characteristic of each individual, however practised in the art of 

 making observations or however attentive he may be. The dif- 

 ference between the time of a man's noting the event and that of 

 its actual occurrence is called his personal equation. It remains 

 curiously constant in every case for successive years, it is carefully 

 ascertained for every assistant in every observatory, it is putilished 

 along with his observations, and is applied to them just as a 

 correction would be applied to measurements made IJy a foot- 

 lule, that was known to be too long or too short by some definite 

 amount. Therefore the magnitude of a man's personal equation 

 indicates a very fundamental peculiarity of his constitution ; and 

 the inquiry I would suggest, is to make a comparison of the age, 

 height, weight, colour of hair and eyes, and temperament (so far 

 as it may admit of definition) in each observer in the various 

 observatories at home and abroad, with the amount of his per- 

 sonal equation. We should thus learn how far the more obvious 

 physical characteristics may be correlated with certain mental 

 ones, and we should perhaps obtain a more precise scale of 

 temperaments than we have at present. 



Another subject of exact measurement is the time occupied in 

 forming an elementary judgment. If a simple signal be suddenly 

 shown, and if the observer presses a stop as quickly as he can 

 when he sees it, some Utile time will certainly be lost, owing to 

 delay in nerve transmission and to the sluggishness of the 

 mechanical apparatus. In making experiments on the rate of 

 judgment, the amount of this iraterval is first ascertained. Then 

 the observer prepares 'nimself for the exhibition of a signal that 

 may be either black or white, but he is left ignorant which of the 

 two it will be. He is to press a stop with his right hand in 

 the first event, and another stop with his left hand in the 

 second one. The trial is then made, and a much longer interval 

 is found to have elapsed between the exhibition of the alternative 

 signal, and the record of it, than had elapsed when a simple 

 sijjnal was used. There has been hesitation and delay : in short, 

 the simplest act of judgment is found to consume a definite time. 

 It is obvious that here, again, we have means of ascertaining 

 differences in the rapidity of forming elementary judgments and 

 of classifying individuals accordingly. 



It would be easy to pursue the subject of the measurement of 

 mental qualities to considerable length, by describing other kinds 

 of experiment, for they are numerous and varied. Among these 

 is the plan of Prof. Jevons, of suddenly e.xhibiiing an unknown 

 number of beans in a box, and requiring an estimate of their 

 number to be immediately called out. A comparison of the 

 estimate with the fact, in a large number of trials, brought out 

 a very interesting scale of the accuracy of such estimates, which 

 would of course vary in different individuals, and might be used 

 as a means of classification. I can im.agine few greater services 

 to anthropology than the collection of the various experiments 

 that have been imagined to reduce the faculties of the mind to 

 exact measurement. They have engaged the attention of the 

 highest philosophers, but have never, so far as I am aware, been 

 brought compendiously together, and have certainly not been 

 introduced, as they deserve, to general notice. 



Wherever we are able to perceive differences by inter-com- 

 parison, we may reasonably hope that we may at some future 

 time succeed in submitting those differences to measurement. 

 The history of science is the history of such triumphs. I will 

 ask your attention to a very notable instance of this, namely, 

 that of the establishment of the scale of the thermometer. You 

 are aware that the possibility of making a standard thermometric 

 scale wholly depends upon that of determining two fixed points 

 of temperature, the interval between them being graduated into 

 a scale of equal parts. These points are, I need hardly say, the 

 temperatures of fre.-zing and of boiling water respectively. On 

 this basis we are able to record temperature with minute accu- 

 racy, and the power of doing so has been one of the most 

 important aids to physics and chemistry as well as to other 

 branches of investigation. We have been so accustomed, from 

 our childhood, to hear of degrees of temperature, and our scien- 

 tific knowledge is so largely based upon exact thermometric 

 measurement, that we cannot easily realise the state of science 

 when the thermometer, as we now use it, was unknown. Yet 

 such was the condition of affairs so recently as two hundred 

 years ago, or thereabouts. The invention of the thermometer, 

 in its present complete form, was largely due to Boyle, and I 

 find in his "Memoirs" (London, 1772, vol. vi. p. 403) a letter 

 that cannot fail to interest us, since it well expresses the need of 

 exact measurement that was then felt in a particular case, where 

 it was soon eminently well supplied, and therefore encourages 

 hope that our present needs as anthropologists may hereafter, in 

 some way or other, be equally well satisfied. The letter is irom 

 Dr. John Beale, a great Iriend and correspondent of Bojle, and 

 is dated February, 1663. He says in it : — 



"I see by several of my own tbetmoneters that the glass- 

 men are by you so well instructed to make the stems in equal 

 proportions, that if we couli name some degrees, .... we 

 might by the proportions of the glass make our discourses intel- 

 ligible in mentioning what degrees of cold our greatest frosts 



dio produce If we can discourse of heit and cold in 



their several degrees, so as we may signify the same intelligibly, 

 .... it is more than our forefathers have taught us to do 

 hitherto." 



The principal experiments by which the mental faculties may 

 be measured require, unfortunately for us, rather costly and,.deU- 

 cate apparatus, and until physiological laboratories are more 

 numerous than at present, we can liardly expect that they will 

 be pursued by many persons. 



Let us now suppose that, by one or more of the methods I 

 have described or alluded to, we have succeeded in obtaining a 



