112 PHILOSOPHICAL TRANSACTIONS. [ANNO 1797. 



the residue after saturation with nitrous gaz, and an electric spark being applied to 

 the mixture of gazes, well dried, a considerable diminution immediately took place, 

 and water was produced ; exp. 4. 



(c) Combustion from hydrogen and oxygen gaz took place, when the tube 

 was about -f- full of gaz, p. 108, exp. 1 ; which was confirmed by passing an elec- 

 trical discharge, under the same circumstances, through a mixture of hydrogen and 

 oxygen gaz, exp. 1. 



(d) Combustion from hydrogen and oxygen gaz took place, when the points of 

 the compasses were accidentally applied to the part of the tube containing gaz, exp. 

 2 ; which was confirmed by passing a discharge, under the same circumstances, 



* through a mixture of hydrogen and oxygen gaz, while the points of the compasses 

 were applied to the tube ; exp. 2. 



(e) The observations made of the kindling of gaz in small quantities, from time 

 to time, during the process of obtaining it, particularly while it was ascending in 

 chains of bubbles, or was adhering to the funnel of the tube, exp. 3, confirm the 

 evidence in favour of this gaz being hydrogen and oxygen gaz. 



The evidence contained under the heads (a) — (e), considered singly and con- 

 junctively, I apprehend, must be admitted by the most rigorous reasoner, to be 

 demonstrative that hydrogen and oxygen gaz were produced by passing electric dis- 

 charges through water. With regard to the origin and mode of production of 

 these 2 gazes, our present observations and experiments do not afford complete 

 demonstrative evidence ; but, though some hypotheses must be admitted, I con- 

 ceive that the body of evidence we possess can afford a satisfactory interpretation of 

 the phenomena. 



Fig. 8, 9, 10, 11, pi. 2, represent the tubes used in producing gaz from water by the interrupted 

 electric discharges. Fig. 1 2 represents the situation of the above tubes during the process of producing 

 gaz from water. Fig. 1 3, 14, represent the tubes employed in producing gaz from water by the first 

 method, with uninterrupted electric discharges. Fig. 15 shows the figure of the tube mounted with a 

 brass funnel used in the 2d method of producing gaz from water by uninterrupted electric discharges. 

 1 Fig. 16 represents the tube blown funnel-wise at the end, instead of being mounted with a brass funnel, 

 as in fig. 15. Fig. 17 represents the situation of the tubes fig. 15 and l6 during the process of producing 

 gaz by the uninterrupted electric discharges. 



VIII. An Experimental Inquiry concerning Animal Impregnation. By 



John Haighton, M.D. p. 150. 



From the experiments of De Graaf on rabbits, we learn, 1°. That the ovaries 

 are the seat of conception. 2°. That 1 or more of their vesicles become changed. 

 3°. That the alteration consists in an enlargement of them, together with a loss of 

 transparency in tneir contained fluid, and a change of it to an opaque and reddish 

 hue. 4°. That the number of vesicles thus altered, corresponds with the number 

 of foetuses, and from these are formed the true ova. 5°. That these changed vesi- 

 cles, at a certain period after they have received the stimulus of the male, discharge 

 a substance, which being laid hold of by the fimbriated extremity of the fallopian 



