July 30, 1891] 



NATURE 



307 



horse-power per ton of machinery had also reached 7*5. The 

 capacity of boilers per indicated horse-power was 2" 17 cubic 

 feet, the heating surface per indicated horse-power 2*6 square 

 feet, the horse-power per square foot of grate 9'4I units, and 

 the coal consumption per indicated horse- power per hour 2"8il 

 pounds. Looking back over the twenty-two years that have 

 elapsed since the Hercules was tried, and remembering the 

 stringent and limiting conditions under which war-ship engines 

 were then designed, one cannot but be struck by the remarkably 

 successful results attained with the engines of the Hercules. No 

 doubt this was due to the extraordinary pains taken in the design 

 and manufacture of the engines of Her Majesty's shi j^s in those days. 

 The introduction of more complex machine tools in the work- 

 shop has enabled much of this minute care and finish to be dis- 

 pensed with, and the advances in metallurgical science have put 

 improved materials at the command of the engineer ; but nothing 

 has yet exceeded, or, we believe, ever will exceed, the beauty 

 and accuracy of the noble examples of the mechanic's art con- 

 structed at the Greenwich shops under the direction of that 

 prince of engineers, the late John Penn. At the same time we 

 gladly acknowledge that the general average of all engines has im- 

 mensely advanced, and is still advancing, both in design, material, 

 and finish. The whole of these three qualities are due to a wider 

 spread of that knowledge of scientific principles upon which the 

 mechanical arts are founded. The manual skill of the handi- 

 craftsman has not increased ; on the contrary, it has deteriorated 

 as mechanical contrivances have superseded the old hand opera- 

 tions. 



From this digression we will return to the table in Mr. 

 Durston's paper, and take one more example. This shall be the 

 Royal Oak, a sister of the Ramillies before mentioned, and one 

 of the eight monster line-of-battle ships now in progress — 

 the biggest war-ships ever yet designed. Laird Brothers, of 

 Birkenhead, are the contractors for the Royal Oak. She has the 

 vertical triple compound engines and ordinary return tube boilers 

 of the present day. The indicated horse-power is put down at 

 13,000,' but will doubtless be much more, the steam pressure 

 being 155 pounds per square inch, and the piston speed 918 feet 

 per minute. The indicated horse-power per ton of machinery 

 is 1 1 75 units, the capacity of boilers per indicated horse- 

 power I "06 cubic feet, the heating surface per indicated horse- 

 power I '55 square feet, and the horsepower per square foot of 

 grate i8*3i units. The coal consumption remains, until the trials 

 are made, a matter of conjecture, but there is every reason to 

 anticipate it will approximate to that of the best performances 

 recorded for Her Majesty's ships — namely, about 2 pounds of fuel 

 per hour per indicated horse-power developed with natural draught. 

 In taking this figure,however, we are somewhat unfair to the earlier 

 engines, for we have taken the other performances of the Royal 

 Oak's engines on forcedidraught, a condition under which the 

 fuel consumption would be much higher. What may be the 

 fuel consumption of Her Majesty's ships under forced draught 

 we have no means of knowing. It should be remembered that, 

 in the Royal Navy, the steam generated in the main boilers is 

 used for the many auxiliary engines also, but the indicated horse- 

 power of the main engines only is taken. Thismanifestly puts the 

 engines of Her Majesty's ships at a considerable disadvantage 

 in the matter of fuel economy when comparison is made with 

 mercantile engines. If we had to summarize the lessons taught 

 by Mr. Durston's tables in few words, we should say the stepping- 

 stones to advance in marine engineering have been multi-tube 

 boilers, compound surface-condensing engines, and forced draught. 

 The latter is still in that state of popular disfavour which seems 

 to be the natural condition of all innovations on established 

 practice; but it will yet make its mark, and lead engine-designers 

 to higher results, whilst it will drive them to more perfect work. 



Mr. Seaton is well known as one of our best marine en- 

 gineers, and is, moreover, a skilled writer, with a special talent 

 for communicating his ideas through the medium of (he pen. 

 That is well proved by his contributions both in the shape of 

 memoirs to technical Societies and also by his well-known work 

 on the marine engine. Unfortunately for the literary side of his 

 reputation he is the manager of one of the largest shipbuilding and 

 engineering establishments in the country, and there are evidences 

 of this in the paper he contributed to the meeting. It was 

 intended to be a counterpart, from the mercantile point of view, 

 of Mr. Durston's naval paper. Mr. Seaton was doubtless 



* The indicated horse-power of the Sardegnea, the big Italian war-vessel, 

 is estimated to be 22,000. This is the largest power yet desigtied for any 

 ship. There are four sets of engines, two for each propeller. 



NO. I 135, VOL. 44] 



anxious to fulfil his promse to contribute to the proceedings, and 

 has evidently done the best time would allow. His paper is a 

 good illustration that "there is always plenty of room at the top," 

 in the engineering, as in all other professions ; but it does not call 

 for any extended notice here. The same thing may be said of Mr. 

 Eldridge's paper, which dealt minutely with technical details. 

 It is, however, a distinctly valuable contribution to the Trans- 

 actions of the Institution, and may be studied with advantage 

 by all naval architects who may have to design steamers for 

 carrying petroleum in bulk — vessels that are fast growing in 

 importance and numbers. 



The meeting terminated with the usual votes of thanks. 



SEVENTH INTERNATIONAL CONGRESS OF 

 HYGIENE AND DEMOGRAPHY. 



T^HE arrangements for this Congress — which will be opened 

 ^ by the President, H.R.H. the Prince of Wales, on Mon- 

 day, August 10, at the first general meeting at St. James's Hall, 

 when short addresses will be given by some eminent foreign 

 hygienists — are now in a very complete state. 



We may mention that the previous Congresses were held in 

 Brussels, Paris, Turin, Geneva, The Hague, and Vienna, at the 

 last of which it was resolved, on the invitation of the Sanitary 

 Institute and the Society of Medical Officers of Health, that 

 the next Congress of the series should be held in London in the 

 present year. 



Besides the Permanent International Committee, to which a 

 number of additional members have been attached for the pur- 

 pose of this Congress, the executive consists of an Organizing 

 Committee, with Sir Douglas Galton as Chairman ; a Recep- 

 tion Committee, with Sir Spencer Wells as Chairman, and Mr. 

 Malcolm Morris as Honorary Secretary ; and a Finance Com- 

 mittee, with Surgeon-General Cornish as Chairman, and Dr. 

 Moline as Secretary. There is also a numerous Indian Com- 

 mittee, with Mr. S. Digby as Honorary Secretary ; and an 

 Editing Committee. Prof. Corfield, whose address at The 

 Hague Congress in 1884 was the origin of the present one (see 

 Nature, vol. xliii. p. 511) is the Honorary Foreign Secre- 

 tary of the Congress, and Dr. G. V. Poore the Honorary 

 Secretary-General. 



The Congress is divided into nine Sections under Hygiene, 

 and one under Demography, which includes Industrial Hygiene, 

 and deals with the life conditions of communities from statis- 

 tical points of view. The Hygienic Sections will meet in 

 Burlington House and in the University of London. They 

 are as follows : — 



(i) Preventive Medicine. President, Sir Joseph Fayrer, 

 K.C.S.I. 



(2) Bacteriology. President, Sir Joseph Lister, Bart. 



(3) The Relations of the Diseases of Animals to those of 

 Man. President, Sir Nigel Kingscote, K.C.B. 



(4) Infancy, Childhood, and School Life. President, Mr. J. 

 R. Diggle, Chairman of the London School Board 



(5) Chemistry and Physics in Relation to Hygiene. Pre- 

 sident, Sir Henry Roscoe, M.P. 



(6) Architecture in Relation to Hygiene. President, Sir 

 Arthur W. Blomfield. 



(7) Engineering in Relation to Hygiene. President, Sir 

 John Coode, K.C.M.G. 



(8) Naval and Military Hygiene. President, Lord Wantage, 

 K.C.B., V.C. 



(9) State Hygiene. President, Lord Basing. 



The Demographic Division will meet in the theatre of the 

 Royal School of Mines in Jermyn Street, under the presidency 

 of Mr. Francis Galton. 



A large number of papers are promi-ed, some on subjects 

 selected by the officers of the Sections, and some on other sub- 

 jects ; indeed, there is such a profusion of papers that it seems 

 very doubtful whether it will be possible to deal with them all 

 during the four days available for the purpose, especially as we 

 are informed that most if not all of the Sections will only sit 

 from 10 a.m. to 2 p.m. 



A vast number of delegates have been appointed from insti- 

 tutions and public bodies in this country. Delegates have been 

 appointed by the Governments of all the European and several 

 other countries, and also by many foreign Universities, cities, 

 public institutions, and scientific societies. There are also a 

 number of delegates from India and the colonies. 



