396 EAMBLES OF A NATUEALIST. [Oh. XXIH. 



night. The following night the same effect was visible, but 

 scarcely so iatense as before (wind N.E., temp. 76°), and 

 on the third night: (the wind being E., and temp. 75°) I 

 again observed it. After this I was ■ absent from Singapore 

 two nights, -and on my. retui-n I no longer, noticed the 

 luminous effect. 



On each of, these three nights, I cai-efuUy examined the 

 water. As I filled a bottle, bright sparks of Kght adhered 

 to my hands, or on briiiging it to the lamp I found -that it 

 contained a number of small globular greenish bodies, which 

 floated upon the surface for the most part, but appeared to 

 have the power of freely moving in the water. On closer 

 examination these bodies proved to be Noctilucae ; and during 

 the night I observed that the contents of. the bottle fe'e- 

 quently flashed with bright and rapid coruscations. I had 

 no difficulty therefore in coming to the conclusion that the 

 peculiar luminosity in the harbour was due to the presence 

 of innumerable Noctilucae. 



On the 24th of May, lying in Simon's Bay, Cape of Good 

 Hope, the water was again luminous, in a manner similar 

 to the occasion just alluded to. The weather was fine, wind 

 W.N.W., light; bar. 30-04, therm. 60°. On examining 

 the water closely, I found that, as before, the luminous 

 effect, though soft, subdued, and apparently uniform, was 

 reaUy due to innumerable small sparks ; and on bringing 

 the water to the light, I found numerous Noctilucse in it 

 precisely similar to those observed at Singapore. They 

 were not, however, in sufficient numbers to have produced 

 aU the light, for in a wine-glassful of water there were on 

 an average not more than a dozen Noctilucse. But besides 

 these bodies there were a great number of motes in the 

 water, many of which appeared, by their rapid jerking loco- 



