

SIGNAL BALLS. 147 



HAMMOCKS. 



Hammocks are manufactured of the perforated and quilted 

 fabrics, described Vol. I. They are well suited for ships' use. The 

 superiority claimed for them consists in their cleanhness. They 

 do not require to be scoured, and are not liable to be infected 

 with vermin. The article is made more complete by the addition 

 of a sheet of napped vellum, of the size of the hammock, which 

 may be drawn underneath it in winter, so that the article when 

 arranged in this way, may be considered warmer in cold weather, 

 and cooler in hot weather than other hammocks ; and if the 

 perforated gum-elastic compound is used, (instead of the other 

 fabrics which are not elastic), a hammock is formed as comfort- 

 able as can be desired, although it will be more expensive than 

 that made of the non-elastic fabrics. See plate , fig. 



TOMPION. 



The outer surface of this article, for the depth of about an 

 inch, is made of gum-elastic sponge ; within it is filled with air 

 or light wood, and is designed as a substitute for the wood tom- 

 pion, which has been heretofore used. Its use is to keep can- 

 non dry and free from rust. This is the invention of an oifi- 

 cer, formerly of the United States' Navy ;* it is evidently an 

 improvement, and may be termed a perfect cannon cork. 



SIGNAL BALLS. 



These are made of plated fabrics, about three feet in diam- 

 eter, and are constructed in the same manner as the self-inflating 

 globes before described. They are designed for signals for ship's 



* Lieut. Seeley. 



