12 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. 



are marked with few letters, not to spoil the engraving ; gg the rete of the tes- 

 ticle ; hh some rectilinear ducts. The other globules were separated from the 

 quicksilver, effused through some of the ruptured vessels, as here delineated, 

 that the engraving might in every respect exactly represent the original prepara- 

 tion; i the flesh of the testicle laid bare (caro testis nuda). 



In fig. 2, pi. 13, aa is the urinary bladder ; b the posterior plane of the longi- 

 tudinal fibres ; c the prostate ; dd the ureters ; e the arteries of the vesiculae ; fg 

 the ductus deferentes at their cellular extremity ; h the right vesicula seminalis, 

 as it naturally appears ; i the seminiferous duct, which perforates the prostate ; 

 1 the left vesicula seminalis, filled with wax ; mm the blind appendages of the 

 vesiculae, which appendages were short in this subject ; nn some branched ap- 

 pendages ; o the seminiferous duct going through the prostate ; p the excretory 

 duct of the vesicula inserted into it. 



Concerning an Aurora Borealis seen Feb. l6, 1749-50. By John Martyn, 

 M.D. F.R.S. Dated Chelsea, Feb. 2\, 17 49-50. N" 494, p. 345. 



On Friday the l6th there was a bright aurora borealis, the northern part of 

 the sky being entirely filled with a pale light, in which frequent coruscations 

 were visible. Besides these lights, there was a perfect uniform arch, extending 

 from east to west, the colour of it was the same with that of the aurora ; with 

 which however it did not seem to have any communication, being placed several 

 degrees to the southward. The shoulders of Orion were visible through this lu- 

 minous arch, in the western part of it, and Cor Leonis in the eastern part. 



Concerning an Aurora Borealis seen Jan. 23, 1750-51. By the Rev. Henry 

 Miles, D.D., F.R.S. N° 494, p. 346. 



On Tuesday, Jan. 23, last, about 6 in the evening. Dr. M. saw a cloud (not 

 large) of an obscure red colour, but much deeper than any he had ever seen 

 before, which rose from the s. w. it was then advancing apace to thcN.E. and 

 quickly reached the zenith, when there appeared a luminous zone, about the 

 breadth of the galaxy, its edges regularly defined, compassing the hemisphere, 

 from the horizon in the n. e. to the zenith, in the same direction in which the 

 above-mentioned cloud had passed, from the s. w. The colour was much 

 fainter, and more luminous, resembling the usual colour of an aurora, and the 

 laminae or streamers soon appeared. 



A Letter from Mr. fVilliam Watson, F.R.S. to the Royal Society, declaring that 

 he as well as many others have not been able to make Odours pass through a 

 Glass by means of Electricity ; and giving a particular Account of Professor 



