224 



SCIENCE 



[N. S. Vol. XXXIII. No. 841 



was a great deal bothered what to do with the 

 overflow flange. After a few nights' worlc I got 

 my Injector fixed and got up steam, and to some 

 extent began clumsily experimenting as the pres- 

 sure rose to 60 pounds, the full working pressure 

 of the boiler. I had the Injector fixed over a tank 

 fed by a ball-tap and closed by the boiler. I 

 turned steam on and was staggered by the rush 

 of water into the tanlc from the overflow pipe, 

 and thought something was wrong. However, I 

 continued to turn the steam spindle, and the 

 escape from the overflow sensibly diminished 

 until I could turn no further. In the meantime 

 the ball-tap started running furiously into the 

 tank, showing me that water was going some- 

 where, and I knew it could go nowhere else but 

 into the boiler. I then began to operate with the 

 four-thread screw at the side, and found that it 

 adjusted the water supply, and succeeded in get- 

 ting the overflow " dry." I then opened the peep- 

 holes opposite the space between the combining 

 and the receiving nozzles, and saw the white 

 steam passing from one to the other on its way 

 to the boiler. I then ceased operations, and had 

 a pipe of tobacco, . . . 



The second chapter deals with the develop- 

 ment of the principle of automatic regulation, 

 by the adoption of which the injector was 

 made to adjust itself automatically to condi- 

 tions imposed by changes in steam pressure. 

 The evolution of the various devices, which 

 have been employed in the accomplishment of 

 this function, is well set forth. Following this 

 are several chapters dealing with the elements 

 of design underlying each of the more im- 

 portant details of the injector, such as the 

 delivery tube, the combining tube and the 

 steam nozzle. These chapters, while consti- 

 tuting the more teclinical portion of the vol- 

 ume, are nevertheless so clearly expressed that 

 the reader emerges from them with interest un- 

 diminished. A chapter entitled " The Action 

 of the Injector " presents an analysis of the ac- 

 tion of the entire instrument with numerical 

 examples. It constitutes a basis for the design 

 of such instruments, and it supplies the 

 means for determining what are the limiting 

 factors under conditions that may be pre- 

 scribed or assumed. The longest chapter in the 

 book, entitled " Applications of the Injector " 

 presents excellent descriptions of the different 



well-known types of injectors now obtainable, 

 with some discussion as to their adaptability 

 to the requirements of different service. 

 Another chapter discusses methods of deter- 

 mining the size of an injector and methods of 

 testing, and presents data derived from tests. 

 A chapter on the requirements of modern rail- 

 way practise deals chiefly with matters affect- 

 ing repairs and renewals, and a final chapter 

 discusses certain problems which arise in 

 practise, in connection with the use of inject- 

 ors in locomotive service. 



At a single point only does it appear that 

 the author slips and this is when he discusses 

 a detail in locomotive practise rather than one 

 affecting injector design or operation, and 

 when a book, as a whole, is strong and true, 

 it is perhaps ungracious in the reviewer to 

 call attention to half a dozen lines which are 

 in no way essential to the purpose of the book 

 and which constitute, in fact, no more than an 

 unguarded suggestion. There are other rela- 

 tions, however, in which the statement be- 

 comes one of some importance, and conse- 

 quently it should not go unchallenged. 

 Under the head of " Feeding Locomotive Boil- 

 ers," the author advises that " in approaching 

 a station at which a short stop is made, espe- 

 cially between long and fast runs, it is 

 advantageous to stop the injector a short time 

 before the station is reached, to permit a 

 slight checking of the fire, and then, when the 

 station is reached, to feed the boilers quickly 

 with one, or even with both injectors if neces- 

 sary, to prevent blowing off at the safety- 

 valve." The practise here outlined is one 

 which has been often suggested and some- 

 times practised. It is, however, objectionable 

 from several points of view, and as a practise 

 should not be tolerated. The water in a loco- 

 motive boiler when the throttle is closed is in 

 a quiescent state. Feed water entering under 

 these conditions is not as rapidly mixed with 

 the water already in the boiler as it is when 

 the throttle is open and the process of ebulli- 

 tion is active. As a consequence the feed 

 entering the boiler while the locomotive is 

 stopped at a station, being comparatively cool, 

 settles in the lower portions of the boiler. 



