Mr. James Duncan Raynolds, of Riverside, Illinois, makes a very intelligent criticism in the American Florist on all that has been written about hot-water pipes flowing up or down hill, and thus sums up his conclusions; " To recapitulate, it seems that to secure the best circulation the following are the proper conditions: (1) Set the heater as far below level of greenhouse flow as possible. (2) Carry the pipes at once to the highest level intended, and keep them high, letting all the fall be a vertical one on returning to the heater. (3) See that air vents are provided wherever a downward turn is made".