February 3, 19 10] 



NA TURE 



407 



cavea or den in which the animals were housed in readi- 

 ness for the performances. Here the debris was found 

 to contain coins of the Emperors Constantine the Great 

 and Hadrian, which indicate the approximate date at 

 which games were conducted by the Romans in this 

 amphitheatre. 



Dr. R. B. Bean, of the Anatomical Laboratory, Manila, 

 publishes an account of a new cephalograph, an instru- 

 ment intended to reproduce the outlines of the human 

 head and face, which he has recently invented. It is 

 based on the cranial instruments of Prof. Rudolph Martin, 

 and is an adaptation of the pantograph. He also issues 

 a further instalment of his examination of the Filipino 

 types in the town of Taytay, which corroborates the con- 

 clusion at which he had previously arrived, that the popu- 

 lation of the archipelago may be resolved into three types 

 ■ — Iberian, Australoid, and Primitive. 



.\ LENGTHY but interesting study of memorising various 

 materials by a new method forms the subject of a mono- 

 graph by Prof. E. .'\. McC. Gamble, separately published 

 bv the Psychological Revie-jL'. In this method a series of 

 colours, odours, or syllables (all three materials are used in 

 different experiments), is repeatedly presented to the sub- 

 ject, who manipulates the members of the series after each 

 presentation and attempts to arrange them in their original 

 order. The repetitions of presentation of the series are 

 continued until successful reconstruction of the order is 

 attained. Miss Gamble terms this method the " recon- 

 struction method," and compares the results with those 

 given by previous methods of experiment in memory. She 

 finds that a relatively small number of repetitions is re- 

 quired for successful reconstruction, even at the outset of 

 the experiments and apart from the well-marked improve- 

 ment-effects of subsequent practice. Compared with the 

 " learning method," in the reconstruction method the 

 increase of difficulty with increasing length of the series is 

 remarkably small. Again, in contrast to the " learning 

 method," in Miss Gamble's method there is no sharp 

 limit to the length of the series which is reproducible in 

 correct order after a single presentation, and the subject 

 remembers fully as many sequences and rather more posi- 

 tions in longer as compared with shorter series. 



The Canadian Department of Mines has issued in 

 advance, from its annual report on mineral production, the 

 chapters by Mr. J. McLeish dealing with chromite and 

 asbestos mining in 1907-8. Canada supplies almost the 

 whole of the world's asbestos, and the Canadian output 

 has Increased steadily from 27,414 metric tons in 1902 to 

 60,372 metric tons, of a value of 190,980 dollars, in 1908. 

 The chief mines are in the eastern townships of the Province 

 of Quebec, especially around Thetford. The Canadian out- 

 put of chromite in 1908 was 7225 short tons (6554 metric 

 tons), a slight increase over that for the previous year, 

 but less than the record in 1906 of 9033 short tons. New 

 Caledonia remains by far the largest producer of chromite ; 

 Turkey is second, and Canada has fallen to the fourth place 

 owing to the rapid development of chromite mining in 

 Rhodesia. 



Dr. V. Conrad has recently investigated the annual and 

 diurnal variations in frequency of 2497 earthquakes which 

 occurred in the Austrian Alps and neighbouring districts 

 from 1897 to 1907 (Mitt, der Erdbeben-Kom. der K. Akad. 

 der Wissen. in Wien, No. 36). The annual variation is 

 well marked, with its maximum in March and minimum 

 in June, the amplitude being 65 per cent, of the mean 

 monthly number of earthquakes. The diurnal variation is 

 also strongly pronounced, the maximum occurring at 

 NO. 2I0I, VOL. 82] 



2 a.m. and the minimum from 8 a.m. to 4 p.m. Treating 

 the hourly numbers of shocks with the aid of harmonic 

 analysis, the diurnal period is found to have a maximum 

 at oj a.m., and an amplitude which is 87 per cent, of the 

 average hourly number of shocks. In all probability this 

 daily change in frequency is due to the varying conditions 

 under which the earthquakes are observed. 



The U.S. Monthly Weather Review for May last (which 

 we have recently received) contains part ii. of Prof. C. F. 

 Marvin's article on " Methods and Apparatus for the Study 

 of Evaporation " (see Nature, November 25, 1909). In 

 this part the author describes the various instruments 

 devised for the experiments upon evaporation of water 

 from lakes and reservoirs undertaken by the Weather 

 Bureau. The different kinds of apparatus, which were 

 designed more especially for evaporation from pans, are 

 clearly illustrated and their use fully explained. Among 

 them is a self-registering gauge invented by Prof. Marvin 

 which records, side by side on the same sheet, rain- 

 fall, wind, and evaporation, and seems to meet in a- 

 satisfactory manner most of the conditions required of 

 such an instrument ; the traces are legible, and the 

 apparatus is said to be portable and easily installed. 



The January number of the Illuminating Engineer of 

 New York contains a well-illustrated article on the electric 

 lighting of the White House, Washington, a dwelling 

 which it characterises as " decidedly unpretentious and 

 plain " in comparison with many mansions of to-day. The 

 imitation candle supporting a miniature incandescent lamp 

 is the unit on which the lighting system is based. In 

 general, they are grouped and supported in an artistic 

 manner, but in one conspi.-uous case the supports are much 

 too massive. 



The United States Coast and Geodetic Survey has 

 recently published an appendix to the report of 1908 which 

 deals with the magnetic observations made on land and by 

 the four vessels engaged in work at sea during the year 

 ending June, 1908. The observations on land are made 

 with a theodolite magnetometer and a dip circle, and those 

 at sea by means of a Lloyd-Creak dip circle checked at 

 intervals by comparison on land with a magnetometer. 

 The whole of the instruments were previously standardised 

 at the Cheltenham Observatory. The present results are 

 summarised in twenty pages of tables. A comparison witli 

 previous results shows that the secular increase of westerly 

 deviation on the Atlantic seaboard is about five minutes 

 of arc per annum. Inland the change becomes very 

 small, but rises again to about four minutes per annum 

 increase in the easterly declination at the Pacific seaboard. 

 It may be noted that these secular changes are not quite 

 in agreement with the representation of them as due to a 

 slow drift of the magnetic system of lines to the west. 



Under the London Gas Act, 1905, the gas companies 

 were relieved of any obligation to remove sulphur com- 

 pounds (other than sulphuretted hydrogen), and to replace 

 the standard Argand burner, London Argand No. i, by 

 another, the London Argand No. 2. The practical effect 

 of this was to enable the gas supplied to be lower in 

 illuminating value by from 1-5 to 2-0 candles. In addition 

 to this, two of the companies were empowered to lower 

 the minimum candle-power from 16 to 14 candles, and in 

 the Gas Light and Coke Company's Act, 1909, the latter 

 company is also permitted to supply 14- instead of i6-candle 

 gas. The 1905 Act also empowered the controlling 

 authority to make tests of the calorific power, and in the 

 1909 Act, which has just come into force, a statutory 

 minimum net calorific power of 112-5 calories per cubic 

 foot is enforced. As compared with the state of affairs- 



