Miscellanies. 191 



The indeterminate use of the word collapse by persons attached 

 to steam boats, and by those who have given accounts of these acci- 

 dents, has probably occasioned most of the misconception which 

 appears to prevail on this subject. Most of the boilers which have 

 failed in this vicinity, were so constructed as to contain large internal 

 flues, which were broken in by the external pressure of the steam 

 upon them, and the term collapse has been used merely to designate 

 the direction in which the disruption has taken place, or rather to in- 

 dicate the portion of the boiler which sustained the injury. 



To illustrate clearly the causes of failure in those boilers which 

 have come under my own observation, would require a prolixity of 

 detail which is not suited to the object of this communication. 



The statement of Professor Renwick, that in our American steam 

 boats " there is never but one safety valve," and that " plates of fusi- 

 ble metal are unknown," is somewhat too broad, and is calculated to 

 mislead the public, in regard to the actual state of what may be called 

 practical science, in this country. Fusible metal was several years 

 ago applied to boilers, as an additional means of safety, mider the 

 directions of the writer, and was also used in other boats navigating 

 from this city. 



Although the strictest attention to the means of safety in steam 

 boats cannot be too often or too strongly urged upon those who con- 

 struct or navigate them, still it is true that much unmerited censure 

 has been dealt out to this class of persons, not only by the ordinary 

 periodical press, but sometimes through the medium of scientific 

 works of a more permanent character. It should always be recol- 

 lected, that an undivided and careful attention to one or two safe- 

 guards of known and acknowledged efficacy, will, in ordinary hands, 

 affoi'd a much greater degree of safety than can be secured by the 

 adoption of all the contrivances with which curious or learned men 

 have from time to time become interested. A due regard to strength 

 in the form and structure of boilers, will remove all reasonable grounds 

 of apprehension, in regard to a mode of travelling which is already the 

 safest, on the whole, of any with which we are acquainted. 



New York, September 24, 1831. 



4. Hurricane of August, 1831.^Inan article which was publish- 

 ed in the April number of the American Journal of Science, I at- 

 tempted to show that storms and hurricanes consist in the regular 

 gyratory motion or action of a progressive body of atmosphere ; 



