Juned, 1878] 



NATURE 



57 



In Fig. 4, ^X representing the direction of sunset or 

 "sunrise," my object is to show that a cloud high up, 

 say at x, when the sun has set so long as to be at s^ in- 



stead of at Xcan really receive light from the sun, and the 

 distance xs" added to ox will represent the total amount 

 of atmospheric absorption undergone by the light. It is 



Fig. 4. 



under these conditions, too, that, in consequence of the 

 reduced illumination of the background, the sky puts on 

 its most beautiful green, which I think is partly a physio- 

 logical effect due to the molecular constitution of the 

 retinas of our eyes. Similarly, by drawing a line from S^ 



we can see how a cloud absolutely in the zenith of the 

 observer at o may have its colour transformed by a 

 considerable atmospheric absorption after sunset. 



J. Norman Lockyer 



THE MICROPHONE IN SURGERY 



C\^ Tuesday at 3 P.M., before a crowded audience of 

 ^^ students and medical men. Sir Henry Thompson gave 

 a demonstration in the anatomical theatre, University 

 College, on the microphone as applicable in operations 

 for stone. 



In old days, the lecturer said, patients used to 

 be sent away when they came to the doctor "because 

 their case was not ripe.." The risk involved in the 

 operation of cutting for stone was so serious that a 

 surgeon seldom liked to undertake it except under com- 

 pulsion, and Avhen cutting had to be resorted to it was 

 not much more difficult to remove a large than a small 

 calculus. In the newer operation of stone-crushing it was 

 better, of course, to have the stone to be crushed as small 

 as possible, and it was essential to deal with the smallest 

 fragments to which the operation reduced it. It was 

 often said, indeed, in objection to lithotrity that to 

 leave even the smallest fragment as a nucleus was to 

 render further treatment necessary and, in time, inevitable. 

 However that might be, it was clearly important to be 

 able to deal with the smallest calculus in the bladder. 



Before going further. Sir Henry Thompson emphatically 

 stated that in his belief the present methods of lithotrity 

 are quite sufficient in the hands of any surgeon of fair 

 practice in the operation to enable him to deal success- 

 fully at all events with almost every case. He compared 

 the use of the new instrument which he was going to 

 describe to that of the endoscope for the urethra, which, 

 however satisfactory on paper, had not been found im- 

 portant in practice, or, better perhaps, to that of the higher 

 powers of the microscope, which were not necessary nor 

 perhaps even advantageous in ordinary work, but which 

 were a valuable resource in questions of unusual difficulty. 



The apparatus consisted of the ordinary feeble battery 

 with wires, connected with two telephones i-unning 

 to different parts of the room, and applied to the 

 ears of the listeners. The ordinary Sound used in 

 operations for crushing the stone was attached by a wire 

 to the circuit of the battery. Near the handle a piece of 

 carbon, such as is used by Prof. Hughes, was carefully 

 balanced and attached by a delicate spring to the battery 

 circuit. When the end of the sound strikes against the 

 smallest piece of calculus the acoustic wave is transmitted 

 along the steel of the instrument to the carbon, where it 

 is transformed into electric vibrations, which are multiplied 

 through the telephone, so that the noise becomes loud and 

 unmistakable. But Sir Henry Thompson pointed out that 

 m practice many things might interfere with the advan- 

 tageous use of the instrument. The carbon arrangement 

 on the soun-l must not be too delicate— not such, for in- 



stance, as could make us hear the walk of the fly like the 

 tramp of an elephant — else the mere friction of the in- 

 strument on the walls of the bladder would produce a 

 noise quite capable of being confounded with that caused 

 by the presence of calculus. The battery must not be too 

 strong, else mere accidental friction of the wires or the 

 noises of the room would produce a distinct sound in the 

 telephone. But when care was taken there would be no 

 difficulty in detecting the noise. An ordinary calculus was 

 put in a bladder in a basin of water, and the listeners 

 could distinctly hear the different noises produced by the 

 point of the sound rasping against the walls of the blad- 

 der or striking the stone. A sharp stroke of the former 

 was sometimes not quite unlike the latter. But with 

 the microphone properly adjusted, and the battery not 

 too strong, it was not easy by trial to detect the presence 

 of even a minute fragment of unremoved calculus in the 

 bladder. The carbon needed only to be fitted to the 

 probe, of course, to detect bullets or fragments of bone. 

 But while it was quite possible for a skilful surgeon to 

 make himself absolutely certain by means of the micro- 

 phone of what he was previously only morally convinced 

 of. Sir Henry Thompson did not appear to anticipate any 

 very remarkable results, at least in ordinary practice, 

 from the use of the instrument. 



NOTES 

 We are happy to state that a Commission appointed by the 

 French Chamber of Deputies has reported favourably on the 

 erection of a large observatory at Meudon, on the site of the 

 Chateau which has been in ruins since the Franco-German war. 

 The credit given is 690,000 francs, which will be paid in two 

 instalments, 345,000 in 1878, and 345,000 in 1879. A large 

 part of that sum, 390,000 francs, is destined for the construction 

 of a large refractor, 250,000 francs are for the buildings, and 

 50,000 francs for the salary of M. Janssen, his assistants, 

 and petty expenses during two years. The credit will be voted 

 very likely neviine obstante. 



We learn, with much satisfaction, that the Swedish Diet has 

 granted the necessary funds to the Meteorological Observatory 

 at Upsala, so well known for the high excellence of its work, 

 and that it will commence its new course as a separate insti- 

 tution, distinct from the Astronomical Observatory, on January 

 I, 1879. 



On Thursday, May 30, Dr. Gladstone, F.R.S., P.C.S. gave 

 a soiree to the Fellows of the Chemical Society at Burlington 

 House. Amongst the numerous objects of interest were the 

 following : — A magnificent collection of immediate principles 

 from the brain exhibited by Dr. Thudichum, who also demon- 



