4 On the means of safety in Steam Boats. 



Experience has taught us the serious lesson, that there are limes 

 when the usual means of safe-guard in steam boats would be una- 

 vailing. Practice has also established extensively the use of that 

 form of boiler which has flues within ; and it may not be reasonable 

 to expect them to be changed, as this would involve much expense. 

 I think this invention will, as to the most formidable cause, make 

 them safe. 



Whenever the occasion of alarm or approach of danger occurs, it 

 will be important to supply water liberally without delay to the boiler, 

 whether the engine be in motion or slopped. Then the supply- 

 chamber described in Mr. Renwick's treatise and represented plate 

 II, fig. 2, (which originated with me some years ago) is well adapted 

 to this purpose. 



I am w^ell convinced there can be no defence but prevention. 

 The effects of the explosion at McQueen's foundery in this city last 

 summer, serves to show that no huhvark that could be erected on 

 the. side of a steam boat, would avail as a protection, but might, by 

 shattering the side, endanger her sinking. 



When we shall have superadded safety to speed in our steam 

 packets, this branch of navigation will be advanced nearly to its prac- 

 tical perfection. 



With the highest respect, I am your friend and humble servant, 



J. L. SlJLLlVAN. 



COPY. 



Specification of a new and useful improvement or invention to 

 guard against the danger of explosions, denominated the Alarm Bell 

 Float and Phonic Guage of Steam Boilers; invented by John L. 

 Sullivan, Civil Engineer ; described as follows, viz. 



The first object of this invention is to cause the ivaier itself to give 

 the alarm, when becoming dangerously low. 



The second object in importance is to use bells or metallic trian- 

 gles, or other sonorous bodies, within the boiler to ascertain where 

 the surface of the water is within certain limits. 



The principle of their operation is founded in the lads which ex- 

 periment has established, that bells or sonorous bodies emit a louder 

 sound in compressed air, than in ihe atmosphere — that the surface of 

 water is favorable to conducting sound, and ihal it will pass through 



