1861J WRITINGS OF JOSEPH HENRY. 445 



loon can be constructed of sufficient size and of sufficient 

 impermeability to gas to maintain a high elevation for 

 a sufficient length of time, it would be wafted across the 

 Atlantic. I would not however advise that the experi- 

 ment of this character be made across the ocean, but that 

 the feasibility of the project should be thoroughly tested 

 and experience accumulated by voyages over the interior 

 of our continent. It is true that more eclat might be 

 given to the enterprise and more interest excited in the 

 public mind generally by the immediate attempt of a pas- 

 sage to Europe; but I do not think the sober sense of the 

 more intelligent part of the community would be in favor 

 of this plan; on the contrary, it would be considered a pre- 

 mature and fool-hardy risk of life. 



It is not in human sagacity to foresee prior to experience 

 what simple occurrence, or what neglect in an arrangement, 

 may interfere with the result of an experiment; and there- 

 fore I think it will be impossible for you to secure the full 

 confidence of those who are best able to render you assist- 

 ance, except by a practical demonstration in the form of 

 successful voyages from some of the interior cities of the 

 continent to the seaboard. 



