3 separate Vintage British standard Institute Publications 

1) Dimensions and Properties of British Standard for Channels and Beams for structural purposes

No4 Dated March 1932

2) Dimensions and Properties of British Standard for Equal Angles & Unequal angles and T Bars for structural purposes

No 4a Dated April 1934

3) British Standard 1806:1951 Dimensions of Toroidal Sealing Rings

No 1 has damage to the front and rear pages but 2 & 3 still in good condition for their age

Please see the photos

Many thanks for looking