20 REPORT OF THE SECRETARY. 



Verj' satisfactory aud consistent results were arrived at from the first 

 series. But in the second series, the cost of the apparatus, the many 

 different circumstances which it was necessary to take into account, 

 the conse(iueut greater care and time required in the investigation, and 

 a hick of money with which to pursue the inquiry to the proper point, 

 IJrevented the establishment of trustworthy data. 



The importance of deciding the questions which it is the specific ob- 

 ject of these experiments to answer need not be urged. There is, how- 

 ever, one interesting circumstance which, among others, was observed, 

 and which may be of importance outside the principal question. This 

 relates to the determination of the condition of the steam as regards 

 its dryness when it entered the heating apparatus; and, as a small 

 quantity of steam was occasionally' allowed to escape after it had passed 

 through the heater, (in order to carry off air,) it was also desirable to 

 ascertain whether any very considerable amount of water, in the condi- 

 tion of mist, was carried away by this escaping steam. 



Hiru's metliod was employed in these determinations. Although the 

 apparatus for this purpose was crude, and for precise experiments would 

 require to be much improved, the experiments seemed to indicate clearly 

 that the steam was nearly if not quite as dry, after passing over the 

 condensing surface of the heater, as before ; that is to say, its " misti- 

 ness " was not increased by its passage over a large extent of condensing 

 surface. These results, if fully verified by a longer series of experi- 

 ments with better apparatus, would indicate that there is a fallacy in 

 the generally-entertained idea that "wet steam" is supplied to an 

 engine if the originally dry steam is led through a long pipe. 



The records of the experiments are voluminous, and it is intended to 

 tabulate them, and to represent the results by curves when the whole 

 are completed. 



Elevations. — It has been mentioned in previous reports that the In- 

 stitution has been at considerable expense in collecting the profiles of 

 canal, railroad, and other surveys, in order to the construction of a to- 

 pographical map of the United States. The charge of this work was 

 given to Mr. Nicholson, topographer to the Post-Oflice Department, but, 

 owing to the absorbing nature of his official duties, he has been unable 

 up to this time to complete it. lu'the mean while Mr. Gardner, of the 

 Hayden expedition, has rendered an important service to this investiga- 

 tion by settling, through critical comparison of various surveys, the actual 

 height of several important places in the interior, which will hereafter 

 serve as points of departure for other surveys. 



Natural History and Ethnology. — Various researches have been made 

 in natural history and ethnology, the aetual expense of which has 

 been defrayed by the Institution, without salary, however, to the person 

 in charge of the work ; an account of which will be given in a subse- 

 quent part of the report. 



