|anuary g, Mi') 



NATURE 



36/ 



. the mismanagemi 1 many mines, the 



unbusinesslike methods employed, and the lack 

 ration and combination amongst mine- 

 owners. He furthei directs attention to .mother 

 drawback, of which all engaged in the manage- 

 ment of mi tal mines in this country are only too 

 \sell aware, in g words: — "Labour in 



non-ferrous mines has in the past been paid 

 on rat the wages have been, more- 



- the reward for part-time 

 having small farms of 

 their own or being habituated to dual occupations. 

 The system is utterly pernicious, and involves 

 great wast • n's time and energy in going 



nd from the scenes of respective work, and 

 tils poor efficiency all round. It has endured 

 from time immemorial, and any change that may 

 : 1 1 mly be very gradually 

 effected. " 



This criticism upon the labour conditions is 

 ', and will be endorsed by even one 

 who knows the system of working, especially in 

 our lead and ;:inc mines. It is evident that with 

 iverished deposits, poor management, and in- 

 ■ nt labour the outlook for the non-ferrous 

 metal-mining industry is not a very bright one. 

 There are, however, a number of other difficulties 

 to be contended with; perhaps the most serious 

 is the question of taxation. It is clearly pointed 

 out that "mines are, at best, wasting assets," 

 and that "in all mines earning profits the amounts 

 distributed to proprietors as dividends or profits 

 insist not only of income, hut include the return 

 oi capital as well. . . . To tax mining profits on 

 iliis basis is to tax capital as well as income, and 

 to differentiate unfairly against persons who in- 

 fo mines." Furthermore, the present system 

 oi taxation discourages the formation of a reserve 

 fund to meet the inevitable fluctuations of mining, 

 and as the report says : "Reserve funds so derived 

 should not be taxed. Similarly, the tax-gatherer 

 should not levy toll upon sums spent out of profits 

 in development." Sir Lionel Phillips does not go 

 on to draw the inevitable inference that the un- 

 happy state of the metal-mining industry has to 

 a large extent been brought about by this in- 

 judicious system of taxation ; it is, however, clear 

 enough that the discouragement of development 

 must tend to leave mines impoverished or ex- 

 hausted, since it prevents the discovery of new- 

 deposits or shoots of ore. It is hopeless to expect 

 a sound policy of management when the accumu- 

 lation of a reserve fund, which should form the 

 basis of such a policy, is mulcted in taxes. Sir 

 Lionel Phillips does not think that compulsion 

 could be applied to force mining companies to 

 side each year out of profits sums estimated 

 as sufficient to redeem their capital; in France, 

 however, the building up of a "legal reserve" is 

 obligatory, and tin system appears to work quite 

 torily. 

 There is very much in this report that will 

 repay careful perusal, and stress may well be laid 

 upon the rei ions which urge the forma- 



tion of a Mines Department for the United King- 

 dom, this Department having for its object the 

 XO. 2567, VOL. 102] 



1 ment of the home mi) 

 industry. The report is careful to point out that 

 nothing more than advice and assistance is re- 

 quired from a Government Department; as the 

 Controller says: "That there has been too little 

 interference by Government in the past will lie 

 iierallv admitted. That there can well be too 

 much interference is equally obvious. . . . Govern- 

 ment cannot, I believe, undertake any industrial 

 work as efficiently as individuals whose material 

 well-being depends upon the result. The nation- 

 alisation of mines would, therefore, be disadvan- 

 tageous to the country. ... In most industrial 

 enterprises, and certainly in mines, there is an 

 element of hazard which fortune-seekers are 

 willing and are bound to take, but which the 

 G01 1 rnment ought not to, and permanent officials 

 never would, take." There is no doubt that these 

 opinions would receive the unanimous endorse- 

 ment of all mining engineers experienced in the 

 direction of British mining enterprises, and it is 

 to be hoped that the Government of the countrv 

 will give heed to the findings of the Controller 

 of this important Department of national industry. 



H. Louts. 



SI PERSATU RATION AND TURBINE 

 THEORY. 1 



1 I has become of late years increasingly obvious 

 •*• that the equilibrium state of saturation, 

 assumed as the basis of the theory of the steam- 

 engine, does not apply accurately to the case of 

 rapid expansion, especially in turbines. Steam 

 in rapid expansion does not even begin to condense 

 until its temperature has fallen far below the satu- 

 ration limit. This fact has been familiar for many 

 years as a general property of vapours called 

 supersaturation, but it was not realised until re- 

 cently that it might produce effects which could 

 not be ignored in practice. Many authorities (e.g. 

 Prof. Rateau, "Flow of Steam," 1905) held that 

 there was no appreciable retard in the condensa- 

 tion even in a steam-nozzle where the expansion 

 reaches the limit of rapidity. On the other hand, 

 Callendar and Nicolson (Proc. Inst. C.E., 1897) 

 found experimental evidence of supersaturation 

 in the cvlinder of a reciprocating engine at com- 

 paratively low speeds. Assuming that the adia- 

 batic of supersaturated steam was simply a con- 

 tinuation of that of superheated steam, they calcu- 

 lated that a loss of 20 per cent, of available heat- 

 drop would result at low pressures if there were 

 no condensation ; but as there was known to be 

 a limit to the state of supersaturation they esti- 

 mated that the actual loss due to this cause would 

 not exceed 5 per cent, to 10 per cent, in practice, 

 depending on the range and rapidity of expansion. 

 The first definite measurement of the super- 

 saturation limit was obtained by Mr. C. T. R. 

 Wilson (Phil. Trans. R.S., 1897) by expanding 

 water vapour mixed with air at 20° C. ft was 

 1 ;hat the mixture could be expanded in the 

 nee of dust or other nuclei without any con- 



" New Theory of the Steam Turbine." By Harold Medway Martin. 

 Reprinted from Engmeei • :?i folding diagrrm. 



