August 31, 1905] 



NA TURE 



437 



single plate of the present series, for which the interval 

 was between four and five years, has had to be rejected. 

 These plates were by Schleussner, on plate glass, and the 

 method of preservation employed by Prof. Donner is ex- 

 plained. 



As regards the length of exposure, Prof. Kapteyn states 

 that, whilst it must be chosen in accordance with the 

 particular work contemplated, it must be such as to give 

 at least one hundred easily measured stars on each plate. 

 Another objection raised against this method was that of 

 accuracy as compared with the older method, but from 

 a comparison of the probable errors now obtained with 

 those obtained at Paris and Potsdam in the carte dii del 

 work. Prof. Kapteyn shows that the advantage is with 

 the new method. He further concludes that to attain a 

 given degree of accuracy the labour involved in the present 

 method is at the very least seven times smaller than it 

 would be by employing the older method. 



The value for the proper motion of the Hyades group 

 adopted by Prof. Donner is 



In R.A. +o"'0900= +0-006245.! 



,, Decl. -o"o25o / 



Reduced to the system given in Publication No. 9, this 

 becomes 



In R.A. +o"'iio7= +0-007675. 



,, Decl. -o"-0259 



which is equivalent to a total proper motion of 

 o"-ii37 in position angle I03°i7. 



The general catalogue contains 395 stars, and of these 

 42 are considered as very probably belonging to the group, 

 xg are given as "probable," and 16 are regarded as 

 " doubtful." 



Variations of Latitude. — In Nos. 4040-4041 of the 

 Astronomische Xachrichten Mr. Kimura, of the Inter- 

 national Latitude Observatory at Mizusawa, gives the 

 results of a series of latitude observations made by Mr. 

 Nakano and himself during the year March 28, 1903, to 

 March 31, 1904. Simultaneous observations of four groups 

 were made each night, their principal aims being (i) to 

 examine whether there exists any regular diurnal change 

 of latitude of a measurable quantity ; (2) to see how large 

 are the systematic differences between the variation of 

 latitude from this (four groups) series of observations and 

 that from the two groups observations for the international 

 service. The mean declinations and proper motions of 

 the stars observed were taken from the international 

 service work, and the value of the " aberration constant " 

 employed was 2o"-5i2. Great care was taken during the 

 reductions to eliminate accidental errors, and it was found 

 that the personal equation between the two observers was 

 practically negligible. The measures and their reductions 

 are given in detail, and lead to the conclusion that " Any 

 systematic diurnal change of latitude of a measurable 

 quantity cannot exist at all." The subsequent com- 

 parison of the results of these observations with those 

 obtained for the international service shows that no 

 systematic differences exist between the four groups 

 observations and the two groups observations made for 

 the international service. 



A Proposed Xew Method for determi.sing the Solar 

 Radiation. — In No. 4037 of the Astronomische Nachrichtcii 

 Prof. Ceraski proposes a new method whereby the absorp- 

 tion of our atmosphere might be eliminated from observ- 

 ations of the changes in the solar radiation. His proposi- 

 tion is that the light of the telescopic planets should be 

 regularly observed photometrically. If the variation of the 

 solar radiation is great enough, it should be shown in the 

 amount of light reflected by the planets, and a long period 

 of photometric observations of these, such as he proposes, 

 would show the sympathetic variations, whilst, if suitable 

 comparison stars were employed, the differential effect of 

 the earth's atmosphere would not affect the results. 



The Cape Observ.4TORY. — The opening paragraphs of 

 Sir David Gill's report for the year 1904 deeply lament 

 the loss sustained by the Cape Observatory, and science 

 in general, by the death of Mr. Frank McClean, F.R.S., 

 tq whose generosity the observatory owes an important 

 part of its equipment. 



NO. 1870, VOL. 72] 



The new transit circle has been thoroughly examined 

 and its observers trained during the past twelve months, 

 and it is now ready for routine work. It was found that 

 by using the Repsold-Struve apparatus, in which a 

 travelling wire actuated by clockwork is employed, the 

 magnitude equation in right ascension observations might 

 be almost, if not entirely, eliminated. 



Preliminary trials of the new sidereal clock showed that 

 the daily rate never varied more than ±0-035. ; but even 

 this is to be improved by a new arrangement by which 

 the top and bottom of the pendulum will be kept at the 

 same temperature. In order to preserve a more equable 

 temperature inside the case, an enclosing chamber 8 feet 

 square and 13 feet high has been erected about it. 



Owing to an unfortunate accident, the driving worm 

 and sector of the Mctoria telescope were damaged, and 

 have had to be sent to Sir Howard Grubb for repair. 

 In consequence, the new objective prism has not yet been 

 tested. 



A number of observations were made with the transit 

 and equatorial instruments during the year, and 185 plates 

 (containing 117,073 stars) for the .\strographic Catalogue 

 were measured. The total number of plates measured is 

 now 760, containing more than 440,000 star images, corre- 

 sponding to about 200,000 different stars. 



In the astrophysical department 74 star-spectra were 

 photographed, and of these 30 have been measured, and 

 a number of radial velocities deduced. 



RECENT ADVANCES IN THE CHEMISTRY 

 OF ALBUMIN.' 



UNTIL recently, one of the main objects in studying the 

 proteids was to classify them into characteristic 

 groups by the aid of certain reactions. This has now 

 given place to problems of a different nature — the investi- 

 gation of the quantitative decomposition of the albumin 

 molecule, the progressive degradation and study of the con- 

 stituent parts, and the determination of the nature of 

 what may be termed the stones of the molecular edifice ; 

 finally, the arrangement of these materials in the con- 

 struction of the albumin molecule. 



The task of separating the constituents of the 

 albumin molecule is still far from complete. The 

 reason for this lies in the difficulty connected with 

 their isolation, for they are particularly troublesome to 

 purify. An important advance was made when Emil 

 Fischer discovered the ester method of separating the 

 amino-acids by distilling them in a vacuum. The 

 method bore immediate fruit in the discovery of phenyl- 

 alanine and a-proline (pyrrolidinecarboxylic acid). Fischer 

 has shown, moreover, that certain amino-acids, like alanine, 

 phenyl-alanine, and serine (hydroxyaminopropionic acid) 

 are invariable constituents of the albumin molecule, whilst 

 hydroxy-a-proline, discovered by Fischer, is another widely 

 distributed constituent. Ehrlich has found that the leucine 

 from albumin, long considered a simple substance, is a 

 mixture of at least two bodies. Hopkins and Cole have 

 succeeded in separating tryptophane in a pure state, a 

 substance which had long eluded the attempts of physio- 

 logists to isolate, and which they have pronounced to 

 be" skatolaminoacetic acid. Skraup has obtained from 

 casein a whole series of new products belonging to the 

 group of diamine- and hydroxyamino-acids — diamino- 

 glutaric acid, diaminoadipic ' acid, hydroxyaminosebacic 

 acid, and caseanic and caseinic acids of unknown structure. 



New substances are constantly being added to the list 

 of what may be termed molecular fragments, which now 

 amount to about twenty individuals. 



There still remains the carbohydrate group of albumins. 

 F. Muller has shown that glucosamine from mucine an4 

 egg-albumin forms an interesting link between the sugar 

 group and the amino-acids. We are still ignorant of the 

 part played by the carbohydrate in its connection with 

 albumin. We cannot say whether it is a loose combination 

 or a mechanical admixture. 



The enormous number of products gives some indica- 

 tion of the complexity of the problem which the study 



1 Abstract of an article by Emil Abderhalden contributed to " Medizinische 

 Klinik," 1905, Nos. i and 2. 



