NOTES ON THE THIRD MEMOIR, PAGE 45. 



By Alfred M. Mayer. 



R£.S0M£ of SIBLIOQBAPET pertaining to the paper "ON A METHOD OF PRECISELT MEASURING THE 



TIBRATORX PERIODS OF TUNING-FORKS, ETC' 



Since the publicatiou of the above memoir I have been enabled to look into publications of 

 learned societies of Holland and Germany, heretofore inaccessible to me, and deem it proper to 

 give the results of those examinations, as it allows me to render credit to others who have antici- 

 pated me in methods described in my paper, and which 1 thought I was the flrst to originate. 

 These methods I Lave, however, developed by my researches into a degree of precision not attained 

 bj those investigators who have anticipated me. The paper of Beetz in Pogg. Ann. I overlooked, 

 although that journal is in my jjossession, and had previously been examined for investigations 

 allied to those of my memoir. 



Apart from the pure pleasure afforded by original investigation, the only reward the man of 

 science has is the credit given him by his fellow-workers in the same lines of research, and as I, like 

 other Americans, have had the experience of seeing my endeavors to advance science overlooked, 

 I know of the injustice thus done — we hope inadvertently — by those who should at least have taken 

 the trouble of searching in accessible journals the cognate work of other investigators before pub. 

 lishing their own. 



Donders, 1865, in Nederl. Archie/, voor Oenus en Natvrlunde, II, page 332, discovered that 

 the spark of the secondary circuit of the inductoiium is conii)osed of several separate sparks, and 

 that one spark is obtained only when the striking distance in the secondary circuit is great. He 

 used a slowly revolving mirror in the same manner as was used by Feddersen (Pogg. Ann., CXIII) 

 in his observations on the electric spark of the Leydeu jar. 



Bonders, 1SC8, Onderzolxingeii gednati in liet Physiologisch Laboraforium der Utrechtsche Eooge- 

 schoul, II, pages 310-318. He sent the spark of the iuductorium from a metallic style attached to 

 the prong of a vibrating fork. The style made its trace on the surface of smoked paper, aud the 

 number of sparks in the discharge and the duration of the discharge were given in the sinuous 

 trace of the vibrating fork. 



Nyland, 1870, Archives NeerlandaiseSj pages 292-337, with ten photographic prints of experi. 

 meuts. Nyland, at the request of Bonders, continued the hitter's experiments of 1868. He shows 

 that the number of sparks iu the discharge diminish with current of battery and with the increase 

 of striking distance in the secondary circuit; shows the effect of increasing the resistance of the 

 medium through which the secondary spark passes ; also, that the duration of the discharge does 

 not diminish iu the same ratio as the resistance to its passage. He obtained a ]>arabolic curve by 

 making the resistance abs(;issas and the durations of discharges the ordinates. On placing a 

 Leyden jar in the secondary circuit and passing the discharge between the points of two styles 

 which were placed near each other, and with tliose points on a line parallel to the axis of rotation 

 of the cylindfir covered with smoked i)aper, he obtained traces which showed an oscillatory action 

 or to-and-fro discharge between the i)oints, similar to the figures obtained by Feddersen (Pogg. 

 Ann., 1862) on a photographic plate, which received from a revolving concave mirror the image of 

 the discharge of a Leyden jar charged with static electricity. Of these traces Nyland says : It is 



167 



