One Thousand Ways to Make Money by Page Fox

552. FROST PROTECTOR.--A chemical combination whose product when ignited

is chiefly smoke. All farmers suffer from late and early frosts. They would pay liberally for a smoke producer which would protect their crops, for it is known that a very little smoke acts as a mantle to keep off the frost. They should be made cheap so that half a hundred might be placed to the acre. Farmers are the most numerous class of people, and fortunes await those who can invent anything for their benefit.