March 28, 1902.] 



SCIENCE. 



515 



ence. The connDarison of the results of the 

 two methods affords a means of determining- 

 relative gravity with more or less accuracy. 

 The results given are preliminary, but, accord- 

 ing to Dr. Helmert, they are suflicient to indi- 

 ■cate that gravity on the ocean where its depth 

 is profound, between Lisbon and Bahia, is 

 nearly normal. Dr. Helmert states that they 

 furnish splendid confirmation of the hypothe- 

 sis of Pratt in regard to the isostatic arrange- 

 ment of the masses of the earth's crust. He 

 states that taken in connection with the re- 

 sults of Nansen's pendulum observations on 

 his North Polar Expedition this hypothesis, 

 from now on, may be reckoned with as a fact 

 at least in the sense of its being a general 

 rule, and he believes that the radial anomalies 

 of the geoid in comparison with the mean 

 ellipsoid will probably not exceed the limits 

 of ± 100 meters previously suggested by him. 



O. H. T. 



BRYAN DONKIN. 



Tl-IE English journals announce the death of 

 Mr. Bryan Donkin, a distinguished engineer 

 and man of science to whom much credit is 

 due for extensive and valuable work in the 

 application of scientific methods in the 

 development of the theory and the art of heat- 

 engine design and construction. His research 

 work has been extensive and continuous and 

 his field of work, applied thermodynamics, 

 mainly, afforded full play for all his energies. 



Mr. Donkin was born in 1835, coming of a 

 distinguished family of whom his father, John 

 Bryan, his grandfather, Bryan Donkin, and 

 the physician. Dr. Horatio Bryan Donkin, 

 were famous members. He was educated at 

 the University College of London and at the 

 Ecole Centrale des Arts et Metiers, in Paris, 

 and later served an apprenticeship in the work- 

 shops of his uncle, at Bermondsey. He then 

 went into business and was sent abroad to erect 

 engines and the heavy machinery of paper- 

 mills, and similar construction. He spent 

 much time in Russia. 



He was a partner in 1868 and the chairman 

 of the corporation in 1889. About 1870, he 

 became interested in the then rare opportuni- 

 ties of scientifically investigating the efiicien- 



cies of the heat-engines and presently made 

 himself one of the leaders in promoting the 

 modern scientific method in engineering and in 

 researches relating to the subject. His 

 influence in the promotion of the movement 

 was exceedingly great and correspondingly 

 useful. He was probably the first to make a 

 complete balance-sheet exhibiting the receipts 

 and expenditures of energy, in the operation of 

 the steam-engine, in such manner as to reveal 

 precisely the extent and the method of dis- 

 tribution of the stream of energy entering the 

 system, its separation into the various currents 

 flowing through the engine and its final dis- 

 position as useful and as wasted energy, and 

 the resultant efficiency of the system. 



He studied the effects of ' cylinder condensa- 

 tion' and of the two correctives of that serious 

 form of wasted energy, superheating and 

 steam- jacketing, and invented the 'revealer' 

 to reveal the then mysterious changes occur- 

 ring in the interior of the engine-cylinder. He 

 established many important facts and laws of 

 thermodynamic operations and thermal action, 

 and was a very earnest advocate of all really 

 sotmd movements in the direction of economic 

 progress. 



He wrote extensively on the subject which 

 came to be his specialty and some of his papers 

 are regarded as among the classics of that de- 

 partment of literature. He published a treatise 

 on gas-engines which has now gone to a third 

 edition and translated Diesel's 'Theory and 

 Construction of the Rational Heat-Motor,' and, 

 in 1898, issued a treatise on the steam-boiler. 

 He was familiar with the French as with the 

 German, and spent much time " on the con- 

 tinent, studying the latest developments in his 

 field, in all countries. 



He was a vice-president of the British Insti- 

 tution of Mechanical Engineers, Watt medal- 

 list,Telford and Manby premium and prize- 

 man of the Institution of Civil Engineers, a 

 member of the Royal Institution and of a 

 number of Eiiropean associations and also of 

 the American Society of Mechanical Engi- 

 neers. 



Mr. Donkin was famous for important and 

 admirable professional work, both in con- 

 struction and in research, was known in all 



