248 
NATURE 
[Fan. 26, 1871 

Ihave. A copy was sent to Messrs. Groombridge in support of 
certain claims on my views about the stars. Let me hasten to 
assure Prof. Reynolds that, as he surmises, the views expressed in 
this very scarce treatise bear not the remotest resemblance to his. 
I read several weeks ago Prof. Reynolds’ interesting paper, the 
views expressed in which are, in a general way, similar to those 
I advocated in a paper entitled ‘‘Strange Discoveries respecting 
the Aurora” in Frazer's Magazine for February 1870. As it was 
quite clear to me, however, that Prof. Reynolds’ views had been 
formed quite independently, it seemed wholly unnecessary to 
comment on that resemblance. I could only rejoice that so 
competent an authority should have been led to conclusions 
agreeing in general so satisfactorily with those I had deduced ; 
and also, be it noted, with the results of the observations made 
on the recent eclipse. RICHARD A. PROCTOR 
Browning’s Spectroscope 
A LETTER from Mr. Browning, in the number of NATURE 
for December 15th, has just come to my notice, and seems to 
require a word from me. I regret exceedingly that he should 
have supposed that I intended to imply that he had committed 
any impropriety in employing in his own automatic combination 
an arrangement of Mr. Rutherfurd’s from a spectroscope which 
was not automatic. I did not ‘“‘go out of my way” in making 
the allusion, but only stated what I supposed to be a fact, in 
order to show that the proposed arrangement of radial bars was 
good and practicable, having already been endorsed by most 
eminent authority. 
At the time when the article was written, Mr. Browning had 
but recently published the account of his instrument, and, of 
course, I knew nothing about its earlier history. 
On the other hand, a full description of Mr. Rutherfurd’s 
arrangements with an illustrative figure had appeared in Si//i- 
man’s FYournal in March 1865, more than four years earlier. 
This article is dated December 10, 1864, and will be found in 
the Journal referred to: vol. xxxix., p. 129. 
Possibly the tone of my allusion may have been unintentionally 
affected by the fact that I supposed that Mr. Browning had seen 
this article. In common with many other Americans, who have 
spoken to me about it, I thought it singular that, in describing 
his own instrument, he made no reference to Mr. Rutherfurd, 
and am very happy to find him blameless in the matter. At the 
same time, I think he has no ground of complaint against me 
for referring to the arrangement as ‘‘first devised by Mr. 
Rutherfurd, and since adopted by Mr, Browning ;” although, if I 
were to write the sentence again with my present knowledge of 
the facts, I should put it quite differently. 
Let me add also that, having seen the instrument to which Mr. 
Lockyer refers in his note, I cheerfully concede to him the priority 
in respect to the use of an elastic spring, and the half prismat the 
beginning of the train, as well as the idea of sending the light 
twice through the train bya right-angled prism at its extremity. 
‘As he has never published an account of his instrument, how- 
ever, I suppose I can hardly be held blameworthy for re-in- 
venting it, and publishing it myself. Without one unkindly 
feeling the words of the old poet still sometimes come to mind, 
“* Fereant qui ante nos nostra dixerint.” 
The magnetic record at Greenwich shows a well-marked 
disturbance of all the elements precisely simultaneous with the 
eruption observed on the sun’s disc September 28th. The 
declination was affected to the extent of five minutes of arc, and 
the disturbance was compounded of two waves, following each 
other, and partly superposed, probably corresponding to the ejec- 
tion of the two masses of protuberance-matter which are shown 
in the figures. C. A. Younc 
London, Jan. 21, 1871 
St. Mary’s Hospital 
I sEE in this week’s NATURE the announcement that Dr. Wood 
has been appointed Lecturer on Chemistry at St. Mary’s 
Hospital Medical School. This is an entire mistake; no 
appointment has yet been made, since Dr. Russell will con- 
tinue to hold the post until the end of the Winter Session. The 
vacancy has not therefure actually occurred yet, although it will 
be declared shortly, and a fresh appointment made in due course. 
W. B. CHEADLE, 
Dean of St. Mary’s Hospital Medical School 
Jan. 20 
[We were misled in making the announcement referred to 
above by our contemporary the Aritish Medical Fournal,—ED.] 


IMPROVEMENT OF GEOMETRICAL 
TEACHING 
A CONFERENCE was held at University College, 
London, on Tuesday, the 17th inst., to take this 
subject into consideration, and to form an Association for 
the improvement of geometrical teaching throughout the 
United Kingdom. 
Previous to the meeting a large number of head and 
mathematical masters and others interested in the subject 
had given in their adhesion to the principles upon which 
it was proposed to form the Association, These included 
representatives of the following important schools :— 
Winchester, Eton, Harrow, Rugby, Charterhouse, Christ’s 
Hospital, Marlborough, Wellington, Clifton, Uppingham, 
Sherborne, Birmingham, Dulwich, University College 
School, London, Repton, Durham, Manchester, King 
William’s College, Isle of Man ; Tiverton, Taunton, Leeds, 
Huddersfield, Nottingham, Yarmouth, Windermere, Mill- 
hill School, Middlesex, Middle Class School, Cowper 
Street, Middle Class School, Bedford, the majority of 
whom were present at the Conference. The movement 
was further supported by Dr. Hirst, F.R.S., of London 
University, Mr. W. Spottiswoode, F.R.S., president of 
the London Mathematical Society, Mr. C. W. Merri- 
field, F.R.S., Principal of the Royal School of Naval 
Architecture, South Kensington, and others. 
Dr. Hirst, the president, took the chair, and resolutions 
were passed bearing upon the organisation and future 
working of the Association. It was proposed to invite the 
mathematicians of the country to prepare syllabuses of 
elementary geometry, embodying their views of the prin- 
ciples which should be adopted in any new text-book 
which is to supersede Euclid. Further particulars may 
be obtained by application to Mr. R. Levett, honorary 
secretary, King Edward’s School, Birmingham. 
A HINT TO ELECTRICIANS 
M® MANCE’S method for measuring the internal 
resistance of a single galvanic element or battery, 
communicated to the Royal Society at its meeting of last 
week, and the modifications of Wheatstone’s bridge 
suggested by myself for finding the resistance of a 
galvanometer coil from the deflection of its own needle, 
supply desiderata in respect to easy and rapid measure- 
ment, which have been long /é/¢ by telegraph electricians 
and xeeded by other scientific investigators and by 
teachers of science. Year after year the latter, 
in their arrangement of batteries, electrodes, and 
galvanometers, have darkly and wastefully followed 
the method which from workmen we learn to 
call rule of thumb; while the former, with ad- 
mirable scientific art, measure every element with 
which they are concerned, in absolute measure. How 
many physical professors are there in Europe or America 
who could tell (in millions of centimetres per second) the 
resistance of any one of the galvanometers, induction 
coils, or galvanic elements which they are daily using? 
How many of them, in ordering an electro-magnet, require 
of the maker that the specific resistance of the copper 
shall not exceed 16,000 (gramme centimetre-seconds) ? 
How many times have eight Grove cells been set up to 
produce a degreeof electro-magnetic effect which four would 
have given, had the professor exacted of the instrument- 
maker the fulfilment of a simple and inexpensive scientific 
condition, as submarine telegraph companies have done 
in their specifications of cables? If every possessor of an 
electro-magnet were to cut a metre off its coil, weigh the 
piece, measure its resistance, and send the result to 
| NATURE, and if every maker of Ruhmkorff coils would 
do the like for every coil of copper wire designed for his 
instruments, a startling average might be shown. And 
what of the items? I venture to say that (provided the 
instruments of the great makers are not excluded) specific 
