708 



SCIENCE. 



[N. S. Vol. XIX. No. 487. 



errors affords no indication. These are given 

 in the following tables, the numbers in which 

 are, as before, in terms of seconds : 



Men. 

 Women. 



70 

 189 



In sum, the excess of general inaccuracy in 

 the estimation of the given periods of time 

 on the part of women, as compared with men, 

 is no less marked than their tendency to over- 

 estimation. The extremes of individual judg- 

 ment are very great; for instance, estimation 

 of the duration of the IJ minute period under 

 condition (3) ran as high as ten minutes. 

 In the case of men the highest was three and 

 one half minutes. The average error of judg- 

 ment among the men, all periods included, 

 was 45 per cent, of the value of the periods 

 estimated; that of the women amounted to 

 111 per cent., or two and one half times that 

 of the men. 



The noting of these sex differences was 

 incidental to the primary purpose of the test, 

 and attention is called to them here in order 

 that observations on the part of others may be 

 brought into comparison with the results pre- 

 sented by this group of persons, all of whom 

 had some acquaintance with psychological ex- 

 perimentation, but few any systematic train- 

 ing in laboratory methods. The writer would 

 be glad to learn whether the judgments of 

 children of the two sexes present a closer 

 approximation in character than those em- 

 bodied in the preceding tables; and, in case 

 they do, whether any systematic test has been 

 made of their progressive differentiation with 

 advance in age. Egbert MacDougall. 



New York Univeesitt. 



THE NATIONAL PMT8ICAL LABORATORY.* 



The annual inspection of the National 



Physical Laboratory by the general board took 



place on March 18, when also a large number 

 of gentlemen interested in physical and me- 

 chanical science accepted the invitation of Sir 

 William Huggins, president of the Royal So- 

 ciety, and of Lord Rayleigh, president of the 

 general board, to examine the work carried on 

 by the institution at Bushy House. All the de- 

 partments of the laboratory were thrown open 

 to the visitors, who were free to go where they 

 pleased, and who found Dr. E. T. Glazebrook, 

 the director, and his assistants ready to give 

 every explanation of the apparatus displayed 

 and the purposes to which it was being placed. 

 The report for 1903 contains full details of the 

 work which was carried out during that year, 

 and also an outline of the program for the 

 present year. In the engineering department 

 this includes a continuation of the research 

 on wind-pressure and of that on the mechan- 

 ical properties of nickel-steels, undertaken 

 jointly with Mr. ITadfield; an inquiry into 

 the specific heat of superheated steam on a 

 large scale; the erection and testing of the 

 new screw-cutting lathe, for which a special 

 house has been built and which is to be used 

 for making standard leading screws on behalf 

 of the Standard Leading Screw Committee 

 of the War Office; and the construction of a 

 machine for determining the friction of bear- 

 ing surfaces. In the physics department, 

 among other things, the construction of a 

 standard ampere balance, together with va- 

 rious electrical tests, is to be undertaken for 

 the engineering standards committee; various 

 methods of measuring temperatures between 

 1,400 0. and 1,800 C, and the suitability of 

 different glasses for high temperature ther- 

 mometry, are to be investigated; the stand- 

 ardization of the steel yard and nickel meter 

 is to be completed, and the urgently required 

 work of compai-ing an ' end ' yard and an 

 ' end ' meter with the ' live ' standards, and 

 of calibrating the subdivisions of each, is to 

 be undertaken; and an inquiry is to be ini- 

 tiated into the conditions in which the pentane 

 lamp may be treated as a standard, and meas- 

 urements made of the refractivity and ab- 

 sorption of various glasses used by opticians. 



* From the London Times. 



