January, 0, 1885. 



SCIENCE 



23 



In physics, Fourier's theorem enables us, 

 from certain measurements of temperature, 

 to determine what will be the probable heat of 

 the earth some time in the future. What we 

 need in psyeholog}' is a psychical theorem, 

 retrogressive in its character. The surround- 

 ings of man daily grow more varied ; and his 

 resemblances to his animal ancestors, it is 

 claimed, are fast disappearing. Now is the 

 time to sound a warning note. Our original 

 psychical sources are disappearing. Instead 

 of weighing a lust}' African who will tip the 

 scales at a hundred kilograms, we shall soon 

 be reduced to weighing ' veridical phantasms ' 

 which we suppose must be below a fraction of 

 a milligram. Back to the original sources, 

 say we ! This is the ciy of all scholars, and 

 ps3chists can form no exception to the general 

 rule. 



LETTERS TO THE EDITOR. 



*% Correspondents are requested to be as brief as possible. The 

 writer's name is in all cases required as proof of good faith. 



The functions of experiment-stations. 



Referring to the editorial comments on this sub- 

 ject in the issue of Science of Dec. 5, I cannot omit 

 to interpose a demurrer to what appears to me to be a 

 somewhat narrow view of the proper functions of 

 experiment- stations in this country, and one which, 

 if understood to be the prevailing one, would quickly 

 put an end to the popular demand for the establish- 

 ment of such stations, especially in the newer states. 



If it is not one of the essential and primary objects 

 of agricultural experiment-stations to render to the 

 agricultural population the scientific aid which they 

 so sorely need when brought face to face with new 

 and untried conditions and factors in a new country, 

 in order to afford them relief from the slow tentative 

 process of blind experimenting by which the solution 

 of practical questions is commonly approached, then, 

 indeed, the raison d'etre of such establishments will 

 be seriously questioned in all but the older states, 

 where the otium cum dv/nitate of purely scientific 

 investigations can be indulged in without leaving un- 

 done things that ought first to be done. 



If the experiment- stations do not do this work for 

 the farmer, who is to do it ? It is not certainly the 

 function of the agricultural colleges as such, al- 

 though in very many cases their greatest present use- 

 fulness assuredly lies in that direction; since their 

 direct influence through the few students who hasten 

 through a superficial course in their halls will long 

 remain insensible, unless supplemented by such prac- 

 tical demonstration of the usefulness of agricultural 

 science as the experiment-station work can afford. 

 P'rom both the practical and the educational point of 

 view, then, those functions to which the article in 

 question allots a second place, should, in my view, be 

 placed first. 



Again: it is said that to unite the two functions of 

 an experiment-station — the scientific and the prac- 

 tical — in one institution and under one management 

 is of doubtful propriety. So far from admitting this, 

 I hold that nowhere can scientific investigation be 

 more fruitful than where, in this direct connection 

 with practice, it is brought face to face with new con- 

 ditions, and therefore with new phases and aspects 

 of old problems. I think it would be a grave mistake 

 to segregate the two branches of the work, whether 

 in space or time, and most especially to intrust the 

 solution of practical problems to persons of inferior 

 qualifications, as is too commonly done, to the detri- 

 ment of the cause of science, and to the disgust of 

 those engaged in pushing it in the face of the difficul- 

 ties it naturally encounters in a new country. There 

 is a limit to the usefulness of differentiation, when 

 each of the segregated branches is thereby tiimmed 

 down to narrowness, and want of proper co-ordinat ion 

 with the other. In our widely varied domain, each 

 location affords peculiar advantages for the prosecu- 

 tion of some branch of both pure and applied agricul- 

 tural science; and those in charge of the several 

 stations should know, or carefully consider, in which 

 direction their greatest usefulness (in the widest sense 

 of the word) lies. 



No one narrow definition of the proper duties and 

 functions of agricultural experiment-stations can 

 apply to all cases alike. Each station will have to 

 adapt its mode and scope of operations to the sur- 

 rounding circumstances; and the good judgment 

 exercised in determining these points will in a great 

 measure determine also the scientific as well as the 

 practical usefulness of such an establishment. With 

 any thing like an adequate endowment, the two 

 branches are not only compatible, but will fertilize 

 each other, as does the combination of investigation 

 and instruction in the case of teachers. The abstract 

 investigator will rarely shape and express his ideas as 

 clearly as the one who is habitually compelled to put 

 them into the proper form for the understanding of 

 others; and the same is measurably true of the ex- 

 periment-stations, in which scientific work, and that 

 intended for the direct instruction of the contempo- 

 rary population, should go hand in hand. It does so 

 even in Europe, where the practical questions needing 

 determination are much fewer and less intricate; and, 

 if it be contended that a different policy should be 

 adopted in this country, the onus of showing the 

 reasons therefor certainly devolves upon the advocates 

 of the new doctrine. E. W. Hilgaed. 



University of California. 



The most economical size of electric-lighting 

 conductors. 



In Science, No. 97, p. 524, Professor Carh art points 

 out an oversight of mine (jSTo. 94, p. 477) in leaving 

 out the cost of waste heat in the conductors as a part 

 of the economy in the Edison three-wire system, and 

 also a mistake in estimating its amount; in both of 

 which I am glad to be corrected. But Professor Car- 

 hart has not, I think, quite reached the most econom- 

 ical result, for the reason that we have the interest 

 on n conductors, but heat developed in only two of 

 them; and, as it seems worthwhile to develop the 

 complete solution for this interesting system, I fur- 

 ther submit the following: — 



Suppose the size of conductors in the two-wire sys- 

 tem to be such that the interest on their cost equals 

 that of the heat-energy developed in them {C' 2 R, 

 using Professor Carhart's nomenclature), which, for 

 simplicity, we will take equal to unity. The general 



