Does the doctrine of contemporaneous exposition apply to a contract where the contract states that the assessment contemplated was the assessment upon which taxes would be imposed in the next year?

I think that in this case the doctrine of contemporaneous exposition may well be applied. It may be conceded that “assessment” is a word capable of diverse meanings dependent upon its context. Here the parties upon the execution of the agreement acted upon it at once, upon the theory that the assessment contemplated was the assessment upon which taxes would be imposed in the next year, and, they having thus interpreted the agreement at the commencement of the 15 years, it is but right that the same interpretation should be maintained throughout. I do not think that much would be gained by attempting a definition of the word “assessment” and discussing its possible meanings. The actions of the parties under this agreement afford, I think, a safe dictionary to aid in its interpretation. An example of a similar application of this doctrine is found in Chapman v. Bluck (1838), 4 Bing. N.C. 187, where there was an agreement for the letting of land and it was uncertain from the documents whether they constituted an actual present demise or referred to a future demise. The conduct of the parties under this arrangement was held to be admissible to shew its construction. Speaking for myself, I should be inclined to regard the true foundation for the decisions as resting upon estoppel. A person who has assumed a construction of a contract, if this is acquiesced in and acted upon by the other party, will not be allowed to assert the opposite construction of an ambiguous expression when it suits his purpose.