ANTHOZOA ASTEROIDA. 153 



however, remained quite unaffected. I need not enter further 

 into detail concerning experiments which gave without excep- 

 tion negative results. 



" So far as the value of these trials is concerned, I would 

 observe, that I by no means consider them as having been 

 sufficient in number, or sufficiently carefully conducted to 

 warrant a positive conclusion as to the non-electrical character 

 of the light of the Pennatula. I was, at the period of their 

 performance, a comparatively young student, and had neither 

 the experience in conducting electrical researches, nor the 

 command of so many or so delicate instruments as I could 

 now make use of for the purpose I had in view. A negative 

 result obtained in such circumstances cannot be considered as 

 having a high value. Nevertheless, did I not consider the ex- 

 periments 1 have recorded as having a positive worth, I should 

 certainly not have published them even with the qualification 

 I append to them. I make them public, however, because I 

 feel quite certain of this, that to produce as long-continued 

 and as bright a light as a single Pennatula will give out when 

 it phosphoresces, by any artificial electrical process, would re- 

 quire an immensely greater amount of electricity than was 

 necessary to affect the least delicate of my electroscopes. If 

 a Pennatula be considered as evolving a small amount of elec- 

 tricity of high tension, like a friction electric machine, then, if 

 we measure the quantity and tension of that electricity by the 

 intensity and continuance of the light, it would powerfully 

 affect the roughest pith-ball electrometer. On the other hand, 

 if we look on the Pennatula as resembling rather a voltaic 

 battery, and as evolving a large quantity of electricity of low 

 tension, then it should deflect very energetically the needle of 

 a galvanometer. Lastly, if we consider the Pennatula as pos- 

 sessing a power analogous to that of the electrical fishes to 

 evolve electricity, both great in quantity, and high in tension, 

 then measuring the amount of these, as before, by the inten- 

 sity of the light, we should have powerful action both on the 

 gold-leaf electrometer and on the galvanometer. As neither 

 of these instruments, however, was affected in the slightest 

 degree, I think my experiments are not without positive value. 

 I should, notwithstanding, have abstained from publishing 

 them until I had repeated them with additional care, had I 



