NEw YorkK AGRICULTURAL EXPERIMENT STATION. 291 
that the blocks be so placed that when the door is forced into 
position it will almost but not quite reach the metal supports 
at the bottom.’ This will admit of some wear before the door 
is down as far as it will go. 
As shown in the illustrations, four strips are required. The 
upper one should be placed at the top of the door so as to press 
the two surfaces of felt as close together as possible, thus lessen- 
ing.the possibility of leakage of gas. To make the pressure on 
the upper part of the door as great as possible the upper strip 
should be warped somewhat and then sprung into place. 
If preferred metal lugs may be cast, together with correspond- 
ing supports, and used in place of the strips and blocks. The 
principal advantage over the wooden fasteners would be that 
they would wear longer. 
To put the door in place it is only necessary to lift it so that 
the ends of the cross strips may drop into the fasteners. Its 
own weight will bring it nearly into place, and it will require 
but little additional force to drive it down as far as necessary. 
The handling of the door will be facilitated if the surfaces of the 
fasteners coming together are lubricated. 
The principal advantage of this fastener over the old is the 
ease and speed with which it permits the door to be put into 
place. It takes but a very few seconds. No ladder is required 
and the delay and consequent expense of turning each button 
into place is avoided. The door is held in place as securely as 
with the buttons, and we have found by careful tests that with 
the new fasteners there is no more danger of leakage of gas 
than before. | 

TSee Bulletin 181, page 1389. 
