THE LECTURE ROOM, SMITHSONIAN INSTITUTION. Ill 



the manner in whicli the principles and conditions investigated in that 

 paper, have heen practically carried out in the arrangements of the 

 Lecture Room at Washington. The subject is so novel, and of so much 

 importance, that we emphatically call the attention of architects and 

 builders to this successful application of scientific research to purposes 

 of public utility. We have only to add, that, from the accounts we 

 have received, we believe that this first attempt to construct on scien- 

 tific principles a room which shall fulfil the requirements of hearing 

 has been entirely satisfactory. The following explanatory description 

 by Professor Henry will be readily understood by reference to the 

 article above mentioned. We need only further add that it will be ob- 

 served, the practicable problem which had to be solved, was not the 

 construction of the most perfect lecture room, in all respects, which 

 the ascertained laws of acoustics, as applicable to public buildings, 

 renderd possible ; but the adaptation, by means of general principles 

 previously ascertained, of some portion of a structure already com- 

 pleted, chiefly with a view to architectural effect, to the purposes of a 

 theatre for public lectures. 



The following is a brief description of the lecture room, which has 

 been constructed in accordance with the facts and principles stated in 

 Professor Henry's memoir on this subject, so far at least as they could 

 be applied. ■ 



There was another object kept in view in the construction of this 

 room besides the accurate hearing, namely, the distinct seeing. It 

 was desirable that every person should have an opportunity of seeing 

 the experiments which might he performed, as well as of hearing dis- 

 tinctly the explanation of them. 



By a fortunate coincidence of principle, it happens that the arrange- 

 ments for insui'iug unobstructed sight do not interfere with those 

 necessary for distinct hearing. 



The law of Congress authorizing the establishment of the Smithso- 

 nian Institution directed that a lecture-room should be provided ; and 

 accordingly in the first plan one-half of the first story of the main 

 building was devoted to this purpose. It was found, however, impos- 

 sible to construct a room on acoustic principles in this part of the 

 building, which was necessarily occupied by two rows of columns. 

 The only suitable place which could be found was, therefore, on the 

 second floor. The main building is two hundred feet long and fifty 

 feet wide ; but by placing the lecture-room in the middle of the story 

 a greater width was obtained by means of the projecting towers. 



The general form and arrangement of the room will be understood 



