306 



SCIENCE 



[Vol. IV., No. 



THE WORK OF OCTAVE HALLAUER. 



The distinguished physicist and engineer, G. 

 A. Hirn, sends to the writer from his sick-bed, 

 where he has been tying, as his amanuensis 

 pathetically writes, ' malade depuis plus d'un 

 mois,' a biographical sketch of his hardly less 

 distinguished and talented assistant, Octave 

 Hallauer. This paper was read before the So- 

 ciete industrielle de Mulhouse on the 30th of 

 January last. Mr. Hallauer died on the 5th 

 of December, of t3 T phoid-fever. He was born 

 at Metz, Jan. 21, 1842, was educated there, 

 and received the degree of bachelor of science 

 in 1860. He continued his studies in mathe- 

 matics, and entered the technical school at 

 Mulhouse at the age of twent} T , making a spe- 

 cial of applied mechanics. He became, at his 

 graduation, an 'apprentice-engineer' at Bit-. 

 schwiller, in the establishment of Stehelin, and 

 afterward joined Leloutre, the agent of the 

 house of Grafenstaden, as his aid and secre- 

 tarj^, at Mulhouse. Later, he became the 

 assistant engineer of the Association des pro- 

 prietaries d'appareils a vapeur, and afterward, 

 January, 1875, the engineer of the Messrs. 

 Hartmann. 



During the Franco-German war, Hallauer 

 served with the French as a lieutenant, and 

 fought in the armies of the Loire, of Orleans, 

 and other sections of the French armj r of de- 

 fence. He was present in the deadly fight at 

 Villersexel, and, after the defeat of the army, 

 took his forces across the Jura Mountains, and 

 retired to Lyons, where he arrived, sick and 

 exhausted, with the portion of his command 

 thus saved. Recovering his health, he re- 

 sumed, at the close of the war, his professional 

 work. 



During the campaign, and at intervals, as 

 opportunities offered, Hallauer frequently va- 

 ried the more serious work which came to him, 

 by the practice of an accomplishment in which 

 he excelled, — that of the painter. His sketch- 

 book was filled with studies of the beautiful 

 scenery of the district in which occurred the 

 operations in which he was engaged. 



The long series of experiments upon the 

 steam-engine in which Hallauer engaged, and 

 which have made him famous, were commenced 

 in 1868. The history of the development of 

 the theoiy of the steam-engine (which now, 

 thanks to the investigations of such men as Hal- 

 lauer, is at last likely to become soon satisfac- 

 torily complete) may be divided, according to 

 Hirn, into three distinct periods : 1°. That in 

 which it was assumed that the heat entering the 

 motor simply traversed the s} r stem, unchanged 



in amount, and acting only by its ' head,' as in 

 the case of falling water, finally reached the 

 condenser without 'loss in quantity, — simply 

 lowered in temperature, and hence, in head 

 available for purposes of impulsion ; 2°. That 

 in which it became recognized, that, in addition 

 to the necessary depression of temperature, 

 there is alwaj's, also, an actual loss of heat b} 7 

 transformation into mechanical energy ; 3°. 

 The experimental period, — that in which it at 

 last became known that the heat supplied to the 

 engine, in addition to these two changes, be- 

 comes seriously modified in its availability by its 

 interaction with the walls of the steam-cylin- 

 der ; which surfaces take up heat from the en- 

 tering steam, and transfer it to the exhaust side 

 without deriving from it useful effect. 



The first period dates from before the time 

 of Carnot. The second period was opened in 

 1852 by the labors of Clausius and of Rankine. 

 The third period has only been entered upon 

 within a few 3'ears past, the experiments of 

 Hirn and Hallauer having furnished a very im- 

 portant part of the basis for the new treatment 

 of the subject. The writer would distinguish 

 these two later periods as those of the ' ideal ' 

 and of the ' real,' in the theory of the steam- 

 engine. Clausius and Rankine, and other writ- 

 ers on the theory of heat-engines, have usually 

 taken no cognizance of the expenditures of 

 steam, other than those involved in the thermo- 

 dynamic relations of energ} T , and ignore the usu- 

 ally greater demand for steam to supply wastes 

 of heat in the steam-cylinder by the processes 

 now familiar to every engineer, as invariably oc- 

 curring in every heat-engine, — those caused by 

 ' cylinder-condensation ' and leakage. The lat- 

 ter can be prevented : the former may be ame- 

 liorated, but can never be wholly prevented, 

 and will probably rarely, if ever, be reduced to 

 such au extent that it may be neglected in the 

 theory of the engine. It usually takes place 

 to such an extent as to render the values of 

 efficiency of fluid, and of engine, and of esti- 

 mated 'duty,' obtained by the purely thermo- 

 dynamic treatment, far from correct, and often 

 very absurd. This fact has in many cases in- 

 duced practically expert engineers to regard 

 the current works on thermod3 T namics as de- 

 void of value and practical interest, forgetting 

 that the correct statement and application of 

 one set of natural laws never can be valueless, 

 even when, as here, other laws may be impli- 

 cated in the same set of phenomena ; which 

 ma} r be equally essential to a complete and 

 correct theory, and which laws may be less' 

 well determined, and their operation less pre- 

 cisely understood. The first essential step 



