March 12, 1886.] 



SCIENCE. 



235 



examination, which are incumbent upon all who 

 propose to enter for a tripos, for French and Ger- 

 man have been introduced as alternative subjects. 

 This will be a great boon to the classical men, who 

 have hitherto been obliged to pass a mathemati- 

 cal examination before they could get classical 

 honors. In fact, the ' additional subjects ' of the 

 ' Little Go ' are merely a relic of the time when 

 candidates for honors in any subject had first of 

 all to graduate in mathematics ; and the result of 

 this was that many of the best classical men con- 

 tented themselves with ordinary degrees. Now, 

 however, all this is changed, and their path to 

 distinction is much easier than it used to be. 



A movement of the same kind is on foot in the 

 University of London also. At a recent meeting 

 of convocation (to which all graduates of a cer- 

 tain standing have the right to belong) a com- 

 mittee was appointed to consider the desirability 

 of the establishment of degrees in engineering. 

 The first meeting of this committee is to be held 

 to-day. It is within the knowledge of the present 

 writer, that many well-established engineers are 

 feeling the want of a knowledge of electricity, 

 and hence it seems desirable, that, for any degree 

 in engineering, a theoretical as well as practical 

 acquaintance with electricity should be exacted 

 from all candidates. 



Probably the most complete private electric 

 installation in the world is now to be found at 

 the house of Sir David Salomons, Bart, at Tun- 

 bridge Wells, about thirty miles south-east of 

 London. On several occasions lately, he has 

 kindly invited parties of leading electricians and 

 engineers to inspect it, and most hospitably en- 

 tertained them there. The boilers, steam-engines, 

 generating-dynamos, etc., are all in duplicate; 

 and opening out of the room containing those, is 

 a large and very complete series of the E. P. S. 

 storage-batteries. Under ordinary circumstances, 

 the engine does not run more than six or eight 

 hours daily. In a sort of annex to the house is a 

 magnificent private workshop, with lathes, saws, 

 planing-machines, and all sorts of ' tools.' The 

 whole of these are worked from two or three 

 motors, which put in motion the overhead shaft- 

 ing. Many thousand pounds must have been 

 spent upon this unique installation. 



The discussion upon Prof. D. E. Hughes's paper, 

 upon " The self-induction of an electric current 

 in relation to the nature and form of its conduc- 

 tor," was concluded last night at the Society of 

 telegraph engineers and electricians. During the 

 three evenings devoted to it, Lord Rayleigh, Prof. 

 George Forbes, Professor Ayrton, Dr. Hopkinson, 

 Prof. S. P. Thompson, Dr. Fleming, Mr. Frank 

 Pope of New York, Mr. Preece, and many others 



expressed their sense of the very great value, in- 

 genuity, and originality, of Professor Hughes's 

 researches, — an opinion which was universally 

 re-echoed in conversation among the members 

 generally. Great applause greeted the proposal 

 with which Dr. Fleming (of the Edison light com- 

 pany) closed a very effective speech, to call the 

 co-efficient of the unit of self-induction a 

 ' Hughes.' Both Mr. Frank Pope and Mr. Preece, 

 as practical telegraphists, pointed out how the 

 experimental results now obtained by Professor 

 Hughes provided a clear explanation of certain re- 

 markable facts observed in telegraphy ; and Mr. 

 Preece paid a warm tribute to Professor Hughes's 

 ingenuity by pointing out, that, whereas the 

 speaker had had to erect a pair of lines two hun- 

 dred and seventy-eight miles in length to com- 

 pare the telegraphic speed of iron and copper 

 wires, Professor Hughes's wonderfully ingenious 

 and delicate induction-bridge had enabled him to 

 predict the same result from experiments upon 

 only ten inches of wire. Perhaps the most im- 

 portant practical feature in the paper was that 

 self-induction in iron wire could be cured by 

 stranding the wire ; but all of the results are a 

 remarkable illustration of science enriched by 

 practice. W. 

 London, Feb. 26. 



BOSTON LETTER. 



The topographical survey of Massachusetts, 

 undertaken by the state in conjunction with the 

 U. S. geological survey, has now been in progress 

 for a year and a half, and about 3,250 square 

 miles have been surveyed, or somewhat less than 

 half the state. The parts already covered include 

 the extreme western border of the state, embra- 

 cing our highest elevations ; two central sections, 

 — one at the Connecticut, and the other around 

 Worcester ; the region about Boston ; and almost 

 the whole of the area to the south of it, lying to 

 the east of Rhode Island, the character of which 

 is very different from other parts of the state, 

 hardly any parts of it being commanded by ele- 

 vated positions. Hence, in surveying this, the 

 plane-table has been laid aside, and the whole 

 district has been mapped by traverse work ; the 

 courses of the streams, and the shore-lines of the 

 open water spaces, being worked in by a winter 

 party taking advantage of the ice. There is also 

 a little completed patch in the extreme north- 

 eastern corner of the state. 



According to an estimate made by the commis- 

 sioners of the survey, the cost of the work the 

 past season has varied from about eight to nine- 

 teen dollars per square mile, and an average of a 



