“ In an ordinary contract for the sale of goods, there is no implied warranty or condition as to the quality or fitness for any particular purpose of the goods supplied, with certain exceptions, and, therefore, the buyer takes at his own risk. The maxim does not apply (a) where the buyer, expressly or by implication, makes known to the seller the particular purpose for which the goods are required, so as to show that the buyer relies on the seller’s skill or judgment, and that the goods are of a description which it is in the course of the seller’s business to supply ”