STUDIES ON MUSEUMS AND KINDRED INSTITUTIONS. 



50' 



museum construction, for it is of tho most vital importance tlmt in the 

 future none shall be built in which provision is not made for the intro- 

 duction of entirely clean air. The atmosphere outside, laden with 

 dust and other injurious sul)stances, depreciates every collection in 

 every possible way, and now 

 that we have found a means 



to obviate this, this means j 



should be emplo3^ed. The in- j 



stallation of Acntilating sys- 1 



tems in Glasgow is on a large £ 



scale and I had an opportu- I 



nity to witness its satisfactory' £ 



operation. It is a serious ques- I 



tion in this connection whether S 



it is necessar}" to keep the win- ^ 



dows completely secured, so c 



that the}' can not be opened, ? 



as thej" are here, or whether I 



such an arrangement should i 



be adopted as in the technical '^ 



school in Manchester, which | 



permits of their being opened, < 



under the condition, however, g 



that the pressure of the air on i 



the inside is alwaj's greater " 



than that from without. This ^ 



is an indispensable prerequi- ^ 



site. This question is impor- E 



tant since the cleaning of se- ; 



curely closed windows from = 



the outside presents great diffi- l 



culties. In the Congressional ~ 



Library in ^^'ashington verj- = 



light, exterior iron galleries = 



are employed, from which the 2 



windows may be cleaned. An- ^ 



other, though more expensive, I 



arrangement would consist in i 



letting the windows revolve I 

 about a vertical central axis 

 and screw the frames on so 

 that the}' are with not too great difficult}' accessible for cleaning from 

 the inside. I believe this latter method is the better, for I fear that 



it would be hard to maintain at all times a higher pressure of air 

 inside than outside. 



In the art school of Glasgow this method of ventilation has also 





