468 Scientific Intelligence. [June^ 



Fourcroy afterwards described it more minutely, and thought it 

 was similar to adipocire. M. Chevreul has, however, since ' 

 found that it differs in some respects from adipocire, especially 

 in not forming a soap with the fixed alkalies, and has proposed 

 to give it the name of cholesterine. MM. Pelletier and Caventon 

 ha% e lately observed the action of nitric acid on this substance, 

 and they have found that a new acid is thus generated, to which 

 they have given the name of cholesteric acid. It forms com- 

 pounds with the alkalies, earths, and metals, the properties of 

 which are all described in a memoir that was presented to the 

 Philoinathic Society. 



IX. On the Crystalline Form of the Deuloxide of Lead. By 

 M. Houton la Billardiere.* . 



The author informs us, that by boiling massicot in a solution 

 of caustic soda, a portion of the metallic oxide is dissolved ; and 

 that after a considerable length of time, the solution deposits 

 white, semi-transparent crystals, of the size of a pin's head, 

 which, by means of a microscope, are easily discovered to be 

 regular dodecahedrons. He performed a series of experiments 

 on these crystals in cider to ascertain their nature, and he satis- 

 fied himself that they consisted of pure oxide of lead. He styles 

 it the deuloxide, because he supposes that there is an oxide with 

 a smaller proportion of oxygen, which may be procured by cal- 

 cining the oxalate of lead ; but it is in fact the protoxide, or 

 yellow oxide of the systematic writers. 



X. On the Formal ion of Coral Reefs, + 



The examination of a coral reef during the different stages of 

 one tide is peculiarly interesting. When the tide has left it for 

 some time it becomes dcy, and appears to be a compact rock, 

 exceedingly hard and rugged ; but as the tide rises, and the 

 waves begin to wash over it, the coral worms protrude themselves 

 from holes which were before invisible. These animals are of a 

 great variety of shapes and sizes, and in such prodigious num- 

 bers, that in a short time the whole surface of the rock appears 

 to be alive and in motion. The most common worm is in the 

 form of a star, with arms from four to six inches long, which are 

 moved about with a rapid motion in all directions, probably to 

 catch food. Others are so sluggish that they may be mistaken 

 for pieces of the rock, and are generally of a dark colour, and 

 from four to five inches long, and two or three round. When 

 the coral is broken, about high water-mark, it is a solid, hard 

 stone ; but if any part of it be detached at a spot which the tide 

 reaches every day, it is found to be full of worms of different 

 lengths and colours, some being as fine as a thread, and several 



» Abridged from Jonrn. Plinrm. f.>r Aug. 1 SIT. 



+ Extracted from Capri Hall's " Account <>f a Voyage of Discovery to the 

 >^eit Coast of Coieu, and the great Loo-choo Island.'' 



