Appendix. 399 



ceptacle. At every sea-port to which ships are bound with unclean 

 bills of health, an apparatus of this kind should be provided, on a 

 scale sufficient for the emergency. And on the Continent, similar 

 provision should be made, at every barrier which is destined to pre- 

 vent the introduction of contagious diseases.* 



It must be obvious that these precautions offer no security against 

 the danger of a contagious disease breaking out in a person who has 

 already been exposed to infection, but in whom symptoms of the 

 disease have not yet manifested themselves. Risks from this source 

 constitute, however, a very small proportion, compared with those 

 arising from fomites ; and they may be easily and effectually guarded 

 against, by insulating the person supposed to be infected, for a period 

 of time exceeding that, during which the seeds of the disease have 

 been ascertained to lie dormant in the animal system. Nor is this 

 proposal meant to supersede the employment of chemical disinfect- 

 ants, especially of preparations of chlorine, in the apartments of the 

 sick ; or their application to articles and fabrics which sustain no in- 

 jury by exposure to those agents. 



I am, Gentlemen, your obedient servant, William Henry. 



JVotice of the J^olcanic Island thrown up between Pantellaria and 

 Sciacca. By William Ainsworth, Esq., M. R. S. L., Member 

 of the Royal Geographical Society, he. 



[From the Magazine of Natural History, &c.] 



The ejection of volcanic masses, or the elevation of the strata of 

 the earth above the level of the soil or sea by natural causes, is of 

 importance, remotely to all theories of the earth, and proximately to 

 the true origin and formation of pseudo and active volcanic rocks 

 and of craters of elevation. 



This branch of geological inquiry has received a new impulse from 

 the late researches of De Buch and Elie Beaumont, and every cir- 

 cumstance which tends to give consistency to opinions more or less 

 theoretically deduced is advantageous to science. 



* No importance is annexed by the writer to any particular form of apparatus ; 

 nor is steam preferred, as the vehicle of heat, for any other reason, than that it 

 affords an effectual security against such a tempeiature as would be injurious to 

 the substances intended to be disinfected. If, in the further progress of inquiry, it 

 should be found that any kind of contagion requires a heat not greatly above 212° 

 Fahrenheit, it may easily be attained, (the articles being still secure from damage) 

 by using steam of higher pressure than that of the atmosphere. 



