VOL. LXVI.] PHILOSOPHICAL TRANSACTIONS. 23 



At La Heese, near Hoogstraeten, by a mean of 22 meridian altitudes of the 

 sun and fixed stars taken in November IJTl, one of which only gives the lati- 

 tude different from the mean of the whole 10'. 2, he determined the latitude of 

 his observatory 51° 23' 2" + n. And by a mean of the observations of Jupiter's 

 satellites, La Heese i» east of the Royal Observatory at Paris Q^ 49' in time, or 

 2° 27' 15". 



At Ostende, by a mean of 24 meridian altitudes of the sun and stars taken in 

 December, one of which only gives the latitude 11 '''.7 different from the mean 

 of the whole, he determined the latitude of his observatory, in the Rue de la 

 Poste, 51° 15' 10' north. And by an emersion of Jupiter's first satellite, the 

 longitude was 2"" 38% or 38' 15", east of Paris observatory. The magnetic de- 

 clination was 20° 35'. 



At Tournai, 1773, by a mean of 14 meridian altitudes of the sun and stars 

 taken in January, one of which only gives the latitude 22". 8 different from the 

 mean of the whole, he determined the latitude of his observatory, in the Rue 

 des Jesuites, 50° 36' 57" + north. The weather would not permit to observe 

 either Jupiter's satellites, or an occultation of a star by the moon, for the longi- 

 tude of Tournai. 



XII. On some Attempts to Imitate the Effects of the Torpedo by Electricity. 

 By the Hon. Henry Cavendish, F.R.S. p. 196. 



Though the proofs brought by Mr. Walsh, (see page, 469, of vol. xiii.) 

 that the phenomena of the torpedo are produced by electricity, are such as 

 leave little room for doubt ; yet it must be confessed that there are some circum- 

 stances, which, at first, seem scarcely to be reconciled with this supposition. 

 I propose therefore to examine, whether these circumstances are really incom- 

 patible with such an opinion ; and to give an account of some attempts to 

 imitate the effects of this animal by electricity. 



It appears from Mr. Walsh's experiments, that the torpedo is not constantly 

 electrical, but has a power of throwing at pleasure a great quantity of electric 

 fluid from one surface of those parts which he calls the electrical organs, to the 

 other ; that is, from the Uf)per surface to the lower, or from the lower to the 

 upper, the experiments do not determine which ; by which means a shock is 

 produced in the body of a person who makes any part of the circuit which the 

 fiuid takes in its motion to restore the equilibrium. 



One of the principal difficulties attending the supposition, that these phe- 

 nomena are produced by electricity, is, that a shock may be perceived when the 

 fish is held under water ; and in other circumstances, where the electric fluid 

 has a much readier passage than through the person's body. To explain this, 

 it must be considered, that when a jar is electrified, and any number of 



