after P completed most of the work, patent owners stated: In consideration of your services as practical manager in working our patents, we hereby agree to give you one-third share of the patents...
can past consideration form good consideration?
past consideration was sufficient
Bowen LJ: .. the fact of a past service raises an implication that at the time it was rendered it was to be paid for, and, if it was a service which was to be paid for, when you get in the subsequent document a promise to pay, that promise may be treated either as an admission which evidences or as a positive bargain which fixes the amount of that reasonable remuneration on the faith of which the service was originally rendered...
parties agreed to exchange shares in their companies, P agreed not to sell 60% of shares for a year (to avoid depressing their value) and D would protect P from any losses (due to fall in value of shares)
subsidary agreement made: P would sell D 60% of shares back at $2.50 within the year, P realised they would lose out if the share price rose above $2.50 so requested D give a guarantee by way of indemnity (only to buy back the shares if the fell below $2.50), D signed in consideration of P having already promised not to sell the shares for a year
was there any consideration for the indemnity?
P's promise not to sell the shares for a year was valid consideration, Privy Council applied Re Casey's Patents 
Lord Scarman: .. an act done before the giving of a promise to make a payment or to confer some other benefit can sometimes be consideration for the promise. The act must have been done at the promisors' request: the parties must have understood that the act was to be remunerated either by a payment or the conferment of some other benefit: and payment, or the conferment of a benefit, must have been legally enforceable had it been promised in advance. All three features are present in this case...
act was carried out at promisor's request
parties understood act was to be rewarded in some way, either by payment or benefit
payment or benefit must have been legally enforceable if had been promised in advance of consideration: must have been agreement, consideration and contractual intention
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