January 30, 1885. 



SCIENCE 



101 



engineers of other countries can learn much 

 from their study. 



He first describes and illustrates the method 

 of constructing the portion of the London 

 underground railway between Aldgate station 

 and the Mansion house, by the way of the 

 Tower. The difficulties encountered from gas 

 and water pipes, sewers, and foundations of 

 buildings, and the necessity of providing for 

 the continuance of street- traffic, called for in- 

 genious contrivances, by means of which the 

 construction was successfully carried forward. 

 Beton or concrete was used for the invert, 

 beton or brick for the side-walls, and brick 

 arches covered the top. All varied in thickness 

 to suit the circumstances of the case, and the 

 superincumbent load. 



Xext follows an account of the building of a 

 tunnel in London for the Midland railway, 

 with illustrations of the timbering employed 

 in the work, and the tunnel cross-section 

 found best adapted to resist the pressure of 

 the London clay. A brief description of a 

 contemplated subway under the Thames at 

 Woolwich is then given. 



The tunnel under the Mersey, between Birk- 

 enhead and Liverpool, a little less than a mile 

 long, communication between the ends of which 

 was opened early in 1884 ; and the Severn tun- 

 nel, not far from Bristol, to be four miles and 

 a half in length, and now well advanced, — oc- 

 cupy in description about one-half of this report. 

 The drainage-tunnel below the main tunnel 

 under the Merse} T ; the arrangements for pump- 

 ing and ventilation ; the introduction of Col. 

 Beaumont's machine, which had previously 

 bored five thousand linear yards through chalk 

 in the proposed tunnel under the English Chan- 

 nel, and here bores a hole seven feet in diam- 

 eter through the sandstone rock, — are well 

 described. The Severn tunnel is prosecuted 

 with drills driven by compressed air. Prog- 

 ress has been hindered from time to time by 

 the influx of water, even to the extent of com- 

 pletely flooding the works. The pumps re- 

 quired are consequently very powerful, having 

 a capacity of eighty-two thousand six hundred 

 cubic metres in twenty-four hours. 



With the exception of two pages devoted to 

 an intercepting or trunk sewer at Brighton, the 

 closing pages are devoted to an account of the 

 examinations and investigations alread} 7 made 

 in regard to a tunnel under the English Chan- 

 nel, between Dover and Calais, the present 

 state of the project, and the possibilities of the 

 scheme. 



The book is handsomely printed, and the 

 illustrations are very clear and explicit. 



NOTES AND NEWS. 



In a lecture at Johns Hopkins on the place of 

 the science of hygiene in a liberal education, Dr. 

 Billings states the objections to the establishment 

 of such a course, as follows: first, that there is no 

 existing demand on the part of students for it ; 

 second, that the subject is not yet on a scientific 

 basis; third, that the present courses of instruction 

 given in the chemical, physical, and biological de- 

 partments of the university, include all that a well- 

 educated man need know of this subject, unless he 

 proposes to make it a specialty ; fourth, that the 

 students have no time for any studies additional to 

 the course already supplied. To the first objection 

 Dr. Billings replied, that the same might be said as 

 to other branches of the curriculum, — that the ma- 

 jority of students do not know what they ought to 

 study, — and that the question is, whether the time 

 has not come to create the demand, and for the uni- 

 versity to lead the way in the matter. The second 

 objection is only partly true. The general rule holds 

 good in man, as it does in the laboratory, that like 

 causes, under like circumstances, will produce like 

 effects. When it has been shown in a number of 

 well-marked cases that polluted water has been the 

 means of spreading typhoid-fever, that overcrowding 

 and foul air precede epidemic typhus, that scarlet- 

 fever or diphtheria has been conveyed to a village by 

 infected clothing from a distance, we have enough 

 information to enable us to advise in similar cases, 

 although we also know that men have drunk sewage 

 with impunity, and that unprotected children have 

 slept in the same bed with a scarlet-fever case and 

 have not taken the disease. 



— The foundations under the stone piers support- 

 ing the iron bridge, twenty-five feet above low-water 

 level, by which the Wabash, St. Louis, and Pacific 

 railway crosses the Kankakee River, have lately been 

 giving trouble. The bed-rock of shale is hard and soft 

 in places in the short space of a few feet. The three 

 piers were built when the water was high, and were 

 placed on platforms of four thicknesses of pine tim- 

 ber twelve inches square. Before these platforms 

 were located, some of the loose material was removed; 

 but it would appear that the foundation was dug 

 deepest in the centre, and the rapid current of high 

 water washed under and disturbed the piers. In 

 order to fill the space, give a firm bearing over all the 

 bottom, make the piers thoroughly durable, and at 

 the same time not interrupt or interfere with the traf- 

 fic over the bridge, the application of wooden wedges 

 was suggested and carried out by P. E. Falcon of 

 Chicago. By a strong jet of water and other appli- 

 ances, the sediment and loose material were cleared 

 away by divers from under two timbers at a time, and 

 the bed-rock was cut away to a level. Oak timbers 

 were fitted to the cavity; and a double row of broad 

 oak wedges, to insure a complete bearing from the 

 middle of the pier to the outside edge, was driven 

 between the oak timbers and the pine platform by 

 means of a steel bar weighing eight hundred pounds, 

 suspended from the bridge by wires, and adjusted to 



