August 3, 191 1] 



NATURE 



161 



to the other is displaced one-half or one-third of the 

 pitch. The pitch is 47 inches, and the rack ensures a 

 quiet motion and permits the trains to work at high 

 speed. 



A paper descriptive ol the Zoelly steam turbine was 

 pi — nted by Mr. H. Zoelly, of Zurich. This turbine is of 

 the impulse type, and as made at the present time has 

 eight stages for turbines running at 3000, twelve stages 

 for 1500, and sixteen stages for 1000 revolutions per 

 minute. The first diaphragm plate of the high-speed 

 turbines has nozzles which extend for a portion of the 

 circumference only in the bottom half of the diaphragms, 

 whilst in the other diaphragms the nozzles usually extend 

 completely round the circumference. In the case of large 

 unit-, steam is admitted through channels extending com- 

 pletely round the circumference for all stages. Governing 

 is effected by throttling the live steam. The efficiency of 

 this type of turbine will be evidenced by the following 

 results for a 4000-kw. turbine : — steam consumption per 

 horse-power-hour at full load. 0-30 lb. ; at about three- 

 quarter load, 9-58 lb. ; at almost half load. 084 lb. ; at 

 about one quarter load, 10-12 lb. A set of two marine 

 Zoelh turbines, each "I 7500 horse-power, has been in- 

 stalled recently in tin- torpedo-boat destroyer G. 173 of the 

 Imperial German Navy. 



Prof. Franz Prasil, ol Zurich, communicated the results 

 of some of his tests on Francis turbines and on Pelton 

 turbines. It is of interest to note that both types have 

 developed in the direction of increase of horse-power per 

 unii since 1900, anil have now reached .1- high .1- 16,000 

 horse-power per wheel. The Francis turbine is applied 

 with success to falls of 3.3 to 402 feet, the Pelton wheel 

 to falls of 131 to 3116 feet. There lias been steady 

 improvement in the construction of the turbines, in the 

 efficiency of the automatic governing, and in the safety 

 mechanism. 



In the case of four Francis turbines in open-wheel pits 

 and working under heads of 44 to 104 metres, tin 

 efficiency was found to be more than 85 per cent, at about 

 So per cent, of full load. Five Francis turbines in spiral 

 wheel cases gave result- -bowing that efficiencies of 85 per 

 cent, and more are attainable in this style of turbine. The 

 heads in the latter case ranged from 11 to 147 metres. 



Four Pelton wheels were tested under falls ranging from 

 qo to 850 metres. At about ^5 per cent, of full load all 

 four turbines showed efficiencies King between S4 and 83 

 per cent. The most favourable efficiencies varied between 

 S4 and Sq per cent. The efficiency was lower than So per 

 rent, onlv under loads which were 25 to 30 per cent, of 

 the full load. 



In regard to efficiency, there is not to be expected much 



further advance in tin- future. The problem of governing 



-ill I..- considered as not yet completely solved, since 



there still appears in view a -eries of applications which 



will influence the further development of this problem. 



THE BELFAST HEALTH COXGRESs. 

 "TMIF annual congress ol the Royal Sanitary Institute, 

 which was held ;1 i Belfast on July 22—29, proved 1 

 great success; and if the papers dealing with the scientific 

 research side were few, those dealing with the administra- 

 tive side of preventive medicine amply made up for this 

 ■lift. It is onlv possible in this short article to 

 uldicate those contributions which were of special interest 

 and importance. 



In a paper upon tin- non-nitrification of sewage in sea- 

 water, Messrs. Purvis, McHattie, and Fisher recorded the 

 results of many experiments, which demonstrated : — " That 

 even after seventy days' incubation of 10 per cent, sewage 

 in sea-water, with every facility for complete aeration, 

 tin re was no production of nitrates or nitrites, and that the 

 free-ammonia figure was increased in the sewage and sea- 

 water at the end of forty-two days. The most obvious 

 explanation of these facts is to assume that the sea-water 

 destroys the useful nitrifying organisms. With regard to 

 the continuous presence of free-ammonia, even after fifty- 

 two days' incubation, it is of interest to note that it 

 supports the suggestion of Kenwood and Kay-Menzies as 

 affording a valuable clue to the contamination of sea-water 

 by sewage." 



Drs. T. Houston and T. Rankin contributed an im- 

 NO. 2179, VOL. 87] 



portant paper upon the diagnostic value of blood reactions 

 in epidemic cerebro-sp : :iaI fever and allied conditions, and 

 they maintain that their observations show that the 

 cerebro-spinal cavity is the proper place to attack the causal 

 organism — the Meningococcus — by means of an anti-serum. 



Dr. Williams, the medical officer of health of the Port of 

 London, contributed a paper on plague precautions in 

 reference to the destruction of rats. After discussing" tin 

 various means of destroying rats aboard of ships, and 

 testifying to the unsatisfactory results obtained from patho- 

 genic bacterial methods, he records the results of experi- 

 ments on the lethal qualities of air containing 3 per cent, 

 sulphur dioxide gas. These experiments indicate that rats 

 and beetles are killed within from two to three hours of 

 exposure to such air. 



In a paper on the viability of B. typhosus in water and 

 its isolation therefrom, Drs. J. Wilson and C. Dickson 

 conclude that uncultivated B. typhosi (viz. those actual!) 

 present in the urine and faces of "carriers") ma\ 

 recovered from water after a period of three weeks 

 two days, when conditions closely resembling those found 

 in nature are imposed. " Dr. Houston was unable to 

 recover uncultivated typhoid bacilli from water at a later 

 period than one week from the time of addition, and 

 stales that ' less than a month's storage of a raw river 

 water is apparently absolute protection against typhoid 

 fever.' Our experiment shows that Dr. Houston's state- 

 ment should be accepted with reserve." 



Dr. King-Kerr, in an interesting and suggestive papei on 

 tin- prevention of typhoid fever, dealt with the experience 

 of Belfast. As recently a- ten years ago the death-rate 

 from typhoid fever in Belfast was a very high one (1-04 per 

 1000 in loot), whereas for the past three years the rate 

 has been cnlv o-o> Dr. King-Kerr explains that several 

 factors were found to have exercised a powerful influence 

 in this reduction, and that their coming into operation was 

 followed by a marked, definite, and even immediate fall in 

 the death-rate. These factors were the substitution of 

 water-closets for privies, the stoppage of the sale of 

 cockles, the establishment of an additional fever hospital. 

 the sterilisation of the infected hospital sewage, and the 

 more complete isolation of typhoid patients. The decline in 

 the typhoid, zymotic, and general death-rates coincides with 

 these operations. 



In a paper on municipal hospitals. Dr. P. Boobbyer 

 directed attention to experiments extending over fifteen 

 vi ars, which had been carried out at Nottingham, to test 

 the value of the open-air treatment for all classes of arut'- 

 specifii diseases, including small-pox, scarlet fever, diph- 

 theria, measles, whooping-cough, pneumonia, erysipelas, 

 and even enteric fever. He was moved to make this experi- 

 ment in the first instance by the reputed liability of isolation 

 hospitals to favour the spread of many (and often com- 

 plicated) cases in confined atmospheres. " During the past 

 frwv vears it has been our constant practice to nurse the 

 more severe cases of tin- diseases mentioned above, as far 

 .1- possible, in the open air. in bell tints with open sides. 

 in the freely ventilated corridors between the various ward 

 blocks of the hospital, or in the covered approaches to the 

 ; ,1 , Cases of an acute and septic character certainly 

 clear up more speedily in the open air than in closed ward- 

 In no -ingle instance, so far as I have been able to discover, 

 has anj untoward result accrued from the exposure." 



I hi State endowment of motherhood, a paper by Dr. 

 Fric Pritchard, aroused considerable interest. He advo- 

 cated that the mother should be endowed in her capacity 

 of mother in order to mitigate the evil effects of poverty 

 and labour upon the woman advanced in pregnancy ; and 

 he impressed the importance of the adequate provision and 

 training of midwives in the principles and practice of infan; 

 feeding and management. The whole object of maternity 

 endowment should' be centred in efforts to safeguard the in- 

 terests of the infant before and immediately after birth, and 

 these interests would be best studied by an efficient midwifery 

 service, supplemented by the domiciliary visits of properly 

 trained health visitors, " both before and after birth; and 

 both midwives and health visitors should be empowered to 

 dispense free benefits of food, clothing, or other necessity 

 which they might think proper for the welfare of the 

 State's new citizen. 



Mr. A. J. Martin's advocacy of a " National Healt.i 

 Week- " met with much acceptance. We cannot expect 



