January i8, 1906] 



NA TURE 



273 



board than those of Hansen, and so there is a better 

 chance of correcting the errors, which no mortal can 

 altogether escape. Next the constants are not stereo- 

 typed, and if it is necessary to change them the effect 

 can be made visible; and for a searching piece of 

 evidence, Prof. Brown has shown already that his 

 calculations remove the last shred of disagreement 

 between the calculated and observed motions of the 

 moon's apse. Finally, in a recent analysis of the 

 Greenwich observations back to 1750, Mr. P. H. 

 Cowell has given a most striking verification of all 

 Prof. Brown's coefficients. 



When Prof. Brown constructs his tables there is 

 an error Hansen fell into which he may be trusted 

 to avoid. In order to improve the agreement with 

 observation, Hansen introduced a certain empirical 

 element. An empirical correction is better than 

 nothing, but it cannot be too clearly recognised that 

 until it is furnished with a theoretical basis it is 

 no more than a mathematical memoria technica. 

 Certainly its place is not in a set of tables, the sole 

 function' of which is to expose correctly and fully 

 the consequences of a clear theory and definite 

 elements, with the view of testing the one and amend- 

 ing the others. R- A. S. 



THE CONTROL OF THE GAS SUPPLY OF 



THE METROPOLIS. 

 ""THE notification of the metropolitan gas referees 

 1 just issued differs in several respects from that 

 for the preceding year, a change necessitated by the 

 provisions of the London Gas Act, 1905. For some 

 years past the London gas companies have been ask- 

 ing for the revision of their Acts, with reference more 

 especially to the system of testing to which their gas 

 is subjected. In the early days of gas supply, when 

 there was free competition and the consumer had the 

 choice of more than one company, no testing was re- 

 garded as necessary, but when, owing to the amalga- 

 mation and consolidation of the gas companies, the 

 supplv became a monopoly, a system of testing the 

 purity and illuminating power of the gas was insti- 

 tuted'. The whole of the arrangements for testing 

 London gas, with the exception of one or two points 

 specially laid down in some of the Acts, are left to 

 the discretion of the gas referees, originally appointed 

 under the City of London Gas Act, 1868. It was 

 alleged by the companies that the requirements of the 

 referees were too stringent and out of touch with the 

 modern developments of gas manufacture. In 

 January, 1904, a departmental committee of the 

 Board of Trade was appointed to inquire and report 

 as to the whole system of gas-testing in the metropolis. 

 At the inquiry the committee heard evidence from the 

 gas referees, and from representatives of the London 

 County Council, the Corporation of London, and each 

 of the three gas companies concerned. It is note- 

 worthy that no actual consumer was heard, although 

 on one of the most important points dealt with by 

 the committee, the question of sulphur impurity, the 

 committee in its report says, " It does not appear that 

 any complaints are made by the inhabitants of other 

 districts on the ground that the gas thus unpurified 

 causes injury to health or is more destructive to 

 articles such as leather, &c, than it is supposed to be 

 in London." 



The report of the committee was almost wholly 

 favourable to the companies. The mode of testing 

 for sulphuretted hydrogen is to be relaxed, a test last- 

 ing three minutes being substituted for one spread over 

 l-i hours, and all sulphur compounds other than sul- 

 phuretted hydrogen may be, and henceforth will be, 

 left in the gas. The evidence of the companies as to 



NO. 189O, VOL. 73] 



the amount of sulphur impurity under the new condi- 

 tions was to the effect that an average of 35 grains 

 per 100 eft. or under might be expected, with the possi- 

 bility of an occasional rise to 40, the maximum under 

 the Acts just repealed being 17 grains in summer and 

 22 grains in winter. The figures for the amount of 

 sulphur present in the gas supplied by the South 

 Metropolitan Company during December last throw 

 ai instructive light on the value of this evidence, the 

 weekly average increasing from 40-8 to 44-6 grains 

 per 100 eft. with a single maximum of 61-3. On one 

 occasion the Commercial Gas Company surpassed 

 even this figure with a maximum of 70.2. It is clear, 

 therefore, that the gas now to be supplied to London 

 may contain about double the amount of sulphur 

 contemplated by the departmental committee, and 

 this is of interest in view of the fact that a Bill is now 

 before Parliament promulgated by various provincial 

 gas companies asking to be placed in the same posi- 

 tion as the London companies as regards the removal 

 of sulphur restrictions. 



In one point the report of the departmental com- 

 mittee was favourable to the consumer. It recom- 

 mended that the standard burner for testing the illu- 

 minating power of all qualities of gas should be the 

 burner at present in use, the Sugg's London Argand 

 No. 1, the gas to be burnt at the rate of five feet per 

 hour. The gas referees in their present notification 

 disregard this recommendation, and prescribe a 

 burner devised bv the engineer to the South Metro- 

 politan Gas Company. The practical effect of this will 

 be to increase the nominal illuminating power of the 

 gas supplied bv those companies having a 14-candle 

 standard. It will be seen, therefore, that the new con- 

 ditions are wholly favourable to the companies. 



There remains" one new point in the gas referees' 

 notification, the prescription of a method of determin- 

 ing the calorific power of gas. The calorimeter, 

 which has been devised by Mr. C. V. Boys, appears 

 to be a distinct advance over its predecessors of the 

 same type, and when it is installed in the testing sta- 

 tions systematic measurements of the calorific power 

 cf London gas will, for the first time, be on record, 

 and will be" available for the next battle on the gas 

 question, calorific power v. illuminating power. 



PROF. C. ]. JOLY. F.R.S. 



THE lamentable death of Prof. C. J. Joly at the 

 1 early age of forty-one closes a career which was 

 likely to influence favourably the mathematical side 

 of astronomy. But his tenancy of the post of Royal 

 Astronomer of Ireland and Andrews Professor in the 

 University of Dublin was, alas! too short for him to 

 make his individuality felt in the science with which 

 he was connected by his occupancy of the chair, that 

 has of late been held by Sir Robert Ball and Dr. 

 \rthur Rambaut. The traditions of the office, and it 

 may be the interrupted work of these astronomers, 

 would naturally compel him for a time to follow cer- 

 tain definite lines which the previous occupants of the 

 chair had approved. But his work in the department 

 of pure and applied mathematics was of a high order 

 and affords abundant evidence of originality and 

 capacity. . . 



From the time that Prof. Joly entered Trinity Col- 

 lege, Dublin, his academic career was marked by his 

 devotion to natural science, and mathematical scholar- 

 ships and studentships were the natural preliminaries 

 that led to a later fellowship. In this position he dis- 

 tinguished himself as a successful teacher of advanced 

 science, but in 1897, when Dr. Arthur Rambaut was 

 appointed to the office of Radcliffe observer, Dr. Joly 



