What contracts are required to be made under the Seal of a company?

Use of common seal: 

 
The common seal of the company shall not be affixed to any instrument except by the authority of resolution of the Board of Directors, and in the presence of at least two Directors and of the secretary or such other person as the directors may appoint for the purpose, and those two directors and secretary or other person as aforesaid shall sign every instrument to which the seal of the company is so affixed in the their presence.