Chemical Science. 185 



hollow glass cylinder of about three inches diameter, of which the 

 glass was nearly three-eighths of an inch thick. The whole was 

 situated about four feet in the rear of the table. About five grains 

 of phosphorus, in two or three lumps, was thrown into about as 

 much of the acid as occupied the tube an inch and a half in 

 height. Very soon afterwards, there was a flash, followed by an 

 explosion like that of gunpowder, and the fragments of the glass 

 cylinder, as well as of the tube, were driven in all directions, so as to 

 break many glass articles at the distance of from five to twenty feet, 

 and to wound slightly some of the spectators. 



On repeating the experiment on a smaller scale with the same 

 acid, similar effects took place, so that Dr. Hare thinks it necessary 

 to strengthen the ordinary precautions given relative to this action, 

 since it may occasionally rise to such intensity as has just been 

 described. 



Professor Silliman adds some statements and remarks, and says, 

 that if the acid be very strong, and especially if warm, the phospho- 

 rus burns with a splendid combustion ; it is thrown about in jets 

 of fire, and requires great caution. To render it the most beautiful, 

 a tall, narrow, deep vessel should be used, but when the quantity 

 of both substances is considerable, there is sometimes a dangerous 

 explosion. * This circumstance has happened so often in my own 

 experience with nitric acid distilled from very pure nitre, and with- 

 out any water in the receiver, that I cannot but repeat the caution, 

 that the operator should be much on his guard. With a stick of 

 phosphorus dropped into two or three ounces of strong nitrous 

 acid, I have known an explosion like that of a swivel, and the frag- 

 ments of glass wounded persons at a distance, although the experi- 

 ment was performed out of doors, and the spectators, formed into a 

 ring, were none of them nearer than fifty feet, and some who were 

 hit were at double that distance*. 



8. ON THE PHOSPHORESCENCE OF CERTAIN SUBSTANCES. 



From the result of numerous experiments made by M. Saladin, he 

 has been induced to conclude that the phosphorescence of many 

 bodies, as dried bones, rotten wood, &c., was caused by the presence 

 of a small proportion of phosphorus evolved by the action of organic 

 matter on the phosphates present, and combining with hydrogen in 

 the nascent state. This action is compared to that upon sulphates 

 in similar circumstances, and has led M. Saladin to several conclu- 

 sions, and particularly to that which implies that phosphorescence 

 (except in the case of certain insects) diminishes with the proportion 

 of phosphates. Experiments are still wanting to prove this point ; 

 but whilst engaged in performing them, M. Saladin is still anxious 

 to secure the credit of priority in taking this view of the effectf. 



* Silliman's Journal, xvi. 366. f Jpurn. de Pharmacie, 1831, 212. 



