All our heat comes from above. This fact patent to all has led me to view the present arrangement of hot water pipes (in part) in greenhouse, stove and pit as against nature's laws and not supported by scientific nor practical knowledge. I have had a long and continued acquaintance with the working of horticultural structures, in the extremes of summer heat and winter cold, and personal experience in their internal working and heating, often attended with serious physical disorganization caused by exposure to the cold draughts from the roof occasioned by the excesssive cold outside acting upon the atmosphere inside even when the thermometer indicated a medium temperature. Among many troubles is the difficulty of commanding the same temperature at the end of the house farthest from the boiler, as that which exists near the boiler. Then there is the renewal of the evils arising from an accumulation of dry hot air Underneath the stages or table on which the plants stand (just where the heat should not be) causing excessive dryness at the bottom of the pot, (so opposite to the working of nature's laws.) All these have led me to think, plan and philosophize shall I say! no; rather to put in practice the great Master-gardener's own, all-wise, perfected arrangements, manifested and shown in the heat of the glorious sun which warms and causeth the earth to bring forth and bud, that it may give seed to the sower and bread to the eater.

I say then that the above experiences and reflections have induced me to partially change the general arrangement of the heating appliance in our glass houses. My boilers are situated at one end of my houses. Now I carry the flow pipe perpendicularly, as direct as is possible from the boiler until it is within, say 18 inches of the apex of the roof. I then divide the stream called the flow, continuing them to the other end of the house (gradually allowing them to fall a few inches in the whole length), then continuing the flows to the sides of the house, I connect them with the pipes underneath the side stages and so return to the boiler. It will at once be seen by those conversant with hot water apparatus, that the more rapid the circulation from and to the boiler, the more perfect becomes the arrangement and service of the system. Now the effect of this is that one commands a complete equable temperature in all parts of the house. Your columns, Mr. Editor, have often been laden with queries and statements of the difficulties and disappointments arising from the fact that the heat of the house, (I refer to houses 100 feet or more long) at the end farthest from the boiler, cannot be maintained at the same temperature as that at the end near the boiler.

Of course I do not take into consideration the economy of utilizing heat to be derived from a flue or smoke pipe proceeding from the boiler through any part of the house. My own experience is, that flues and smoke pipes have always been attended with great trouble, risk, and are unreliable. Now the advantages I claim by following nature's own laws in this respect and application of the same are briefly summed up thus:

1. More rapid and perfect circulation from and to the boiler. 2. Full command of the upper strata of air, and consequently the whole temperature of the house. 3. A perfect equable temperature throughout the entire length and breadth of the house. 4. The prevention of an accumulation of dry, hot, unhealthy air underneath the stages or tables on which the plants stand. 5. Consequent upon this last the fact that plants will not suffer from drought at the bottom of the pot when from the appearance of the surface of the soil they are moist.

Now Mr. Editor/eighteen months ago I altered the piping in one of my houses (100 feet long by 22 feet wide) by carrying the flow pipes above, and the results were so satisfactory that during last autumn I rearranged one other of my houses (100 by 18) and shall embrace the first opportunity to alter all my houses to this arrangement.

In this community my procedure has been severely criticised by men who profess to know; men who are reported to be well versed in scientific knowledge; but doctors differ, and err so frequently that we often learn from the merest novice, much that is more sensible. To cite one instance of the ignorance which prevails even among scientists:

Not long ago, just subsequent to the alteration of the second house, a scientific friend on visiting my nursery denounced in toto the arrangement and stated emphatically that I was going against all scientific knowledge and practice. Just a week after this denunciation another scientist visited the nursery, admired the arrangement, spoke of it as based on true scientific principles, and stated that I was carrying out an idea that would revolutionize our present system of heating.

I hope my horticultural friends will not persuade themselves that I am advocating that which I do not believe in, but rather that which I have acted upon, and will act upon more extensively in the future.