"Royal SoQiety, 3^3 



He has found it impossible to give a sufficiently ample and 

 distinct view of the numerous and important discoveries 

 which have been made in the science during the two last 

 years," without extending the work to a second volume. 

 And as its original title would but ill accord with the en- 

 larged form under which the book will now appear, it will 

 be changed to that of '* Elements of Experimental 

 Chemistry." 



LIX. Proceedings of Learned Societies, 



ROYAL SOCIETY. 



vJn the 3d, 10th, and 17th of May, the reading of Mr. 

 Macartney's observations on luminous insects was con- 

 tinued. The result of the author's researches has enabled 

 him to state that J 2 dift'erent genera of insects, which in- 

 clude an immense number of species, emit light. Seven 

 of these genera belong to the order of moLlusca^ and the 

 other five to the hemipterous, as the J u Igor ce ; the apte- 

 rous, as the cancer pulex and Julge?iSj &c. Mr. Macartney 

 took an historical survey of what has been written on lu- 

 minous insects, related the discoveries of different voyagers, 

 such as those of Sir Joseph Banks, who discovered two 

 species, the cancer pulex near Madeira, in 1774, with 

 capt. Cook, and the medusa noctiluca, Capt. Horsburgh 

 also discovered two species in the Arabian sea, which he 

 gave to the author, one of them like a wood louse, the 

 other he called medusa scintdlans. The same accurate ob- 

 server also noticed various luminous appearances of the sea, 

 and some insects, which on being pressed eniit a lumi- 

 nous fluid. He also gave to Mr. M. a drawing of one of 

 the insects, which he took out of the water at a time when 

 the sea appeared almost white, like a vast field of ice 

 covered with snow. This appearance is ascribed by the 

 author to immense quantities oi medusa scinlillanSf which 

 emit flashes of light, and so frequently as to assume a con- 

 tinued brightness. To this species of medusa the author 

 attributes the sudden flashes of light which are occasionally 

 seen on our own sea shores. Mr. M. has also discovered 

 three different species of luminous insects on the southern 

 coasts of Kngland. In the course of his inquiries, he ap- 

 pears to doubt the luminousness of the cancer pulex, but 

 notices the pyrosoma ataLantica^ a worm -shaped luminous 



