582 



NA TURE 



[Al'RIL 23, 1908 



with Lummer-Gc-hrcUe plates, arc cited for tlic sal<c of 

 comparison : — 



A = 5790 ( Yellow line). 



Ob;erved «A Inleosity Janicki Baeyer 



-0266 ... i ... -0-251 ... — 



-0-170 .. tV •.■ -0-187 ■• -0-19 



-0-I22 ... i ... -0-II9 ... -0-127 



-0-077* ••• I •■• — •■- ~ 



-0-032* ... h ... — ■■• ~ 



Principal Line Princip.il Line Principal Line 



+ 0-035* ••• i •■■ — ■■• — 



+ 0-073 ••• 4 •■• +0-084 ... — 



+ 0-142 ... J ... +0-132 ... +0-139 



+ 0-189 ... i ... +0-168 ... — 



+0-235 ... I ... +0-230 ... +0-237 



A = 546 1 [Green line). 

 tensity Janicki 



4 ... -0-232 



Observed 6A Intensity Janicki Baeyer 



-0-247 ... J ... -0-232 ... -0-250 



-0-216" ... J ... — ... — 



-0-175* ■•• i ••• — •■• — 



-0-142* ... i ... — ... — 



-Olio .;. J ... -0099 ... -0107 



-0-084 ..■ I •.• — .. -0-072 



-0-058 ... J ... -0-066 ... -0-051 



-0C24 ... j ... — ... -0-025 



Principal Line Principal Line Principal Line 



+ 0-033* -.. T ••■ — ••• — 



+ 0068* ... j ... +O-0S8 ... +0087 



+ 0-109* .. i ■■. — •■■ — 



+ 0-143 ■■• i •■• +0-133 ■•• +0-132 



+ 0-201* ... i ... — ... — 



+ 0-230 ... j ... — ... +0-222 



Some of the Hnes not observed b_v Janicki and Baeyer, 

 and marked with an asterisk, seein to be new, but the 

 scanty literature on spectroscopy at my disposal does not 

 permit me to conclude which of them were observed for 

 the first time. 



Of the numerous satellites of the green line, —0.232, 

 observed by Janicki, is separated into two lines, —0-247 

 and —0.216, and —0099 into two, — o.iio and -0.084. 

 The lines —0216 and +0033 are evidently the same as 

 — 0.208 and +0.032 given by Gray and Stewart. The 

 satellite +0-087 observed by Baeyer, +0088 by Janicki, 

 + 0-093 by Gc-hrcke and Baeyer, +-0-082 by Fabry and 

 Perot, and +0.084 ^y Houston is resolved into two com- 

 ponents of nearly equal intensity, +0.068 and +0.109. 

 Gray and Stewart give only +0.067. The green line was 

 separated into twenty-one components by Lummer and 

 Gehrcke . with a single interference plate ; here it is 

 separated into fifteen lines. Some of these lines will be 

 separated into components by increasing the resolving 

 power. 



The spectrum produced by heating an ordinary vacuuin 

 tube of H-shape containing a few drops of mercury, and 

 excited by an induction coil, gave results almost coinciding 

 with those of Janicki, as observed by Mr. .Amano and 

 myself. The appearance of the satellites seems to be in- 

 fluenced greatly by the construction of tfie tube and the 

 mode of excitement. H. Nag.aoka. 



Physical Institute, Tokyo University, March 15. 



Mendelian Characters among Shorthorns. 



I WAS much interested in Prof. James Wilson's letter 

 in Nature of April 2, and I sent the number to my friend, 

 Mr. William Duthie, of Collynie, Tarves, Aberdeenshire, 

 a well-known breeder of Shorthorns of the first class, in 

 the hope that Mr. Duthie, from his own experience, might 

 check some of the numbers given by Prof. Wilson. Mr. 

 Duthie sent my note to Dr. Thomas F. Jamieson, of 

 Ellon, who is also a famous breeder of Shorthorns, as 

 well as an agricultural chemist of repute. Dr. Jamieson 

 wrote to Mr. Duthie, and I have the authority of both 

 to send the following extract from his letter, which will 

 interest, not only Prof. Wilson, but also those who may 

 be collecting statistics regarding the Mendelian aspects 

 ot the problem of heredity : — 



" I have long been of opinion that the Shorthorns have 

 arisen from a combination of a rod breed and a white one. 



NO. 2008, VOL. 77] 



There is a remarkable tendency in them to produce animals 

 which are entirely white (unless, perhaps, the ears), more 

 so, I think, than those which are entirely red, and I find 

 that of the white calves the majority are females. 1 

 would like you to test this latter point from your own 

 knowledge, in order to see if you also find it so. There 

 is no doubt that a red bull mated with a red cow will 

 almost always produce a red calf, more especially if the 

 bull's own parents were both red, and similarly with 

 white upon white. My red bull "Topsman," 63,447, gave 

 me 113 calves, and not one of them white. He was mated 

 eleven times with a white cow, and the result was ten 

 roans and one red. He was mated sixty times with a red 

 or red-and-white cow, and every one of the calves was 

 red. He was mated forty-two times with a roan cow, 

 with the result that twenty-three of the calves were roan 

 and nineteen red. " Topsman " had white socks on' the 

 hind shanks, and several of his calves had so too, probably 

 about twenty-six of them, or 23 per cent." 



John G. McKendrick. 

 Maxieburn, Stonehaven, .April 11. 



lonisation of Air by Ultra-violet Light. 



Since Lenard has shown that ionisation of the air is 

 produced by light of short wave-length, it has seemed 

 advisable to extend his researches into the region of the 

 extreme ultra-violet, discovered by Schumann, and to 

 investigate the effect on air of light of wave-length below 

 A 1850. 



For this purpose, a discharge tube filled with hydrogen 

 to a pressure of i mm. of mercury, and a screen-cell, were 

 used, both similar to those descriljed by Prof. Lyman in 

 the Astropliysical Journal, March. Below the screen-cell 

 was a chamber where ionisation took place. Dry, dust- 

 free air was blown through this chamber into a cylindrical 

 condenser system. The ionisation produced by the light 

 from the vacuum tube was measured by the charge acquired 

 by one of the cylinders, the other being kept at a constant 

 potential. The air pressure in the screen-cell could be 

 varied at will. Precautions were taken to guard against 

 surface effects. 



Under these conditions, it has been found that the 

 ionisation increases in a most marked degree as the 

 pressure in the screen-cell is decreased. It is, therefore, 

 evident that ionisation is produced in air by light from 

 that part of the spectrum discovered by Schumann, and 

 that the effect increases considerably with decrease in 

 wave-length, at all events, in the neighbourhood of 

 A 1800. 



It is proposed to investigate the effect in some of the 

 elementarv gases. Frederic Palmer, jun. 



Haverford College, Haverford, Pa., U.S.A., 

 April 10. 



THE INTERNATIONAL MATHEMATICAL 

 CONGRESS AT ROME. 



THE congress of 1908 has been considerably larger 

 than its three predecessors. L'p to April 4, the 

 ollicial membership list contained 64S names, but later 

 additions have increased the number of those present 

 to about 530 niembers, and 167 ladies accompanying' 

 them. The weather has been of the same unsettled 

 character that we are accustomed to describe as 

 " British Association weather," but the brilliancy of 

 the gatherings has not been materially affected bv the 

 spells of rain. 



The proceedings commenced with a reception at 

 the University, given by the rector (Prof. Tonelli) on 

 Sunday, .April 5, but the congress was formally opened 

 0.1 the following morning in the Hall of the Horatii 

 and Curiatii at the Capitol, in the presence of the 

 King, when addresses were read by Mr. Nathan, 

 Mayor of Rome, by Prof. Blaserna, representing the 

 Reale Accademia del Lincei, and by the Minister of 

 Public Instruction. 



A discourse was afterwards read by Prof. Vito Vol- 

 terra on mathematical progress in Italy during the 



