This section is from the book "Cassell's Cyclopaedia Of Mechanics", by Paul N. Hasluck. Also available from Amazon: Cassell's Cyclopaedia Of Mechanics.
A window sash frame with a double pair of sashes is employed often for deadening outside noise. The accompanying illustrations show such sashes and frames, Fig. 1 being a vertical section and Fig. 2 part of a horizontal section.

Fig. 3.

Fig. 1.

Fig. 2. Double Sashes for Deadening Noise.
 
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