Dr. Alexander Mayer, of Paris, announces that he has been able to obtain heat ior all the purposes for which heat is now used, by means of friction. An apparatus ior this purpose will soon be exhibited to the public.— ]Ex. [This is nothing new. Water has been boiled by friction frequently, but it requires more physical and mechanical force to raise the heat than the amount of pswer derived from it by re-action. Tile cheapest way of obtaining heat is by the combustion of fuel.