■82 PROCEEDINGS OF THE ACADEMY OF [1888. 



and which he had obtained through the kindness of Mr. George F. 

 Kunz. The specimen was of especial interest on account of the re- 

 port (see Nature. Dec. 1, 1887. xxxvii, p. 110) that Professor Lat- 

 chinof and Jerofief had detected in the insoluble residue small cor- 

 puscles having all the characters of diamonds. 



The speaker had extracted from the fragment in his possession 

 two small oval bodies with extremely high index of refraction and 

 showing only slight traces of polarization, such as is common to 

 many diamonds. They Avere colorless and transparent, resembling 

 certain specimens of Brazilian "bort." Having been able to dis- 

 tinctly scratch a polished sapphire with portions of the meteorite, he 

 was disposed to agree with Professor Latchinoff and Jerofief that 

 these bodies were true diamonds. The olivine in this meteorite was 

 also in the form of oval grains and had a deep yellow color and 

 bright polarization. The rounded form of the olivine and the dia- 

 monds may have been due to corrosion of the igneous mass. This 

 rounded form is very commonly shown by the olivines in basic erup- 

 tive rocks. 



AVhile diamonds have never before been found in meteorites, car- 

 bon has long been known in them in its graphitic or amorphous form. 

 Recently Fletcher ' has described under the name of Cliftonite a 

 cubical form of carbon, somewhat harder than ordinary graphite, 

 which he found in an Australian meteorite. 



The important bearing of the present discovery upon the vexed 

 question of the diamond is evident. The speaker had recently en- 

 deavored to show that the commonly received notion that itacolumite 

 was the original matrix of the diamond is a mistake, and that dia- 

 monds really occur in, or in the neighborhood of, basic eruptive 

 rocks.^ The facts regarding the associations of the diamond in 

 Africa, Borneo, New South Wales, California and elsewhere all 

 point to peridotites or allied rocks as the matrix of the diamond. 

 The similarity, both in structure and composition, of the diamond- 

 bearing Kimberlite of South Africa to meteorites had been pointed 

 out by the speaker previously, and he had, in view of this fact, sug- 

 gested the search for diamonds in meteorites. 



Ctenophores in Fresh Water: — Dr. Benjamix Sharp reported 

 that he had observed in a fresh water pond at Sachecha, Nantucket, 

 a great number of Ctenophores, in apparently good condition. This 

 pond is occasionally opened to the sea to allow the escape of the percli 

 that breed there is great numbers. The Ctenophores without doul)t 

 found their way into the pond at such time. As far as he could de- 

 termine they were the common Mnemlopsis Leidyi, unchanged by 

 their strange environment. They not only appeared perfectly healthy 

 and active but were highly phosphorescent at night. He was not 



' Jour. Mineralog. Soc. vii, p. 121, 1887. 



•^ Proc. Brit. Assoc. Adv. Science. Manchester, 1887. (See Geolog. Magazine, 

 March. 1888.) 



