JOURNAL OF HOKTICULTURE AND COTTAGE GAKDENER. 



[ January G, 1&70. 



should be given sparingly at the root. In April shift the 

 plants into 6 or 7-inch pots, and set these on coal ashes in a 

 sheltered situation, protecting the plants from frost and ex- 

 oessive wet by hoops and mats. Water freely in summer, and 

 do not allow any blooms to expand the first year, but cut them 

 close cff. Transfer the plants to the blooming pots, using 

 8-inch or even 9-inch pots for large plants, and continue them 

 out of doors until October ; then place them in a cold frame, 

 or, better still, a cool, airy, dry house, from which they can 

 be taken into the forcing house r,s required, but forciog ought 

 not to begin until the middle of December ; the beginning of 

 January is a good time to commence forcing. The tempe- 

 rature from fire heat should not exceed 55° at night ; indeed, 

 Carnations should be brought on as gradually as l'inks. 



Since the introduction of the varieties known as Tree Car- 

 nations, blooms of this class of plants have not been scarce, 

 even in winter. To flower them well in winter, it is necessary 

 to keep them from flowering the first year, but they should be 

 repotted as they require it, so as to have them in 8 inch pots 

 by autumn, nipping off the tops of such as are disposed to be- 

 come straggling, and no flower-stems should be allowed to rise 

 until autumn. The cutting-back or shortening should be 

 practised during the spring and early summer months, the 

 plants being kept well exposed to the light in a cool, airy 

 greenhouse or cold pit. Free ventilation should be given day 

 and night. When the plants have made a good growth, and it 

 has matured, expose them fully to the open air until the end 

 of September, and then house them. It a rather warm green- 

 house or conservatory they will flower during the greater part 

 of the winter and spring. A temperature of 45° at night is 

 sufficiently high for plants to bloom continuously through the 

 winter. They may be forced, and in this case the temperature 

 should be from 50° to 55° at night, so as to have them in 

 flower at the required time. The best compost is two thirds 

 loam from rotted turves, one-sixth of old cow dung, and one- 

 sixth leaf soil, with a free admixture of sharp sand. Good 

 drainage is necessary. 



If allowed to grow at will, and bloom in summer, the Tree 

 Carnations are the most miserable of all winter-flowering 

 plants, and to see them as they are generally seen, with shoots 

 twisted round stakes, and very much longer than the flower- 

 stalks, is anything but likely to create a taste for their culture ; 

 and how seldom are they seen in flower in winter ! For winter- 

 blooming they must be specially prepared, and then they are 

 free-floweiing. — G. Abbey. 



BOILERS AND BOILING. 



Your readers ought to be much obliged to Mr. Peach for 

 bringing forward this subject ; I believe it has not been before 

 discussed in a scientific yet popular manner. So much igno- 

 rance is evinced by the public in all connected with heating by 

 hot water, that it is high time the theory of it were better 

 understood. 



I entirely differ from Mr. Peach's manner of reasoning ; and 

 I believe Urmly that water is so bad a conductor of heit that 

 when a fire is applied to it from above little or no effect is 

 produced, because I am sure the principle of conduction fails 

 in such a case, and of course convection cannot take place. A 

 bottle of water placed under a fire grate would be heated on all 

 sides as if it were in an oven, and would afford no means of 

 comparison with one hung in front of the fire. Supposing a 

 box feet high and 1 foot square were placed on end and filled 

 with water, the top being in contact with the bars of a large 

 furnace, would the whole of the water ever boil ? No. Sup- 

 posing the box to be hung over a furnace and the sides effectu- 

 ally screened from heat, would not the whole of the water be 

 boiling in a very short time ? Yes. A very thin portion of 

 water may become hot from conduction alone, provided the fire 

 is continued long enough. As the water is circulating in a 

 boiler it does not remain long enough in one place to he heated 

 by conduction ; moving water or particles can only be heated 

 by convection. The laws of radiation, conduction, and con- 

 vection apply as surely to the water contained in a horticultural 

 boiler as to the water in steam or other boilers. I can assure 

 your readers that the most elaborate experiments have proved 

 the truth, that water cannot be heated to any practical amount 

 by fire above it. If a cylindrical boiler were entirely surrounded 

 by fire it would evaporate very little more water than if the 

 lower haif only were used for the heating surface. 



The exact quantity of 4-inch pipe which one superficial foot 



of boiler exposed to the direct action of the fire will heat is 

 58 feet; only 1 foot of flue surface is to be reckoned for every 

 3 feet the boiler actually contains. If a boiler is perfectly set 

 it will do this amount of work, but it is better to count on less 

 being done. Mr. Peach mentions a boiler of his heating 430 feet 

 of pipe. I should like to hear what the total heating surface 

 is, measured on my plan, not counting the top, and only 1 foot 

 for each 3 feet of flue surface. I imagine it is not less than 

 8 feet. 



As to the tubular boilers alluded to, I never remark on con- 

 temporaries' inventions. If I made a tubular boiler I should 

 place the tubes as vertically as I could, and shape them like 

 inverted cones. 



The feed-pipe should go into the lowest part of the boiler, 

 and the expansion or relief-pipe into the highest point of the 

 apparatus ; why, I need not explain. 



The rule I gave for calculating the quantity of pipe is not 

 my own, but is by a far cleverer man — Mr. Hood ; it gives a 

 large quantity of pipe, and is to be depended upon. Mr. Peach 

 is right in saying the radiating power of glass varies with the 

 angle at which it is fixed. 



It cannot possibly take more fuel to keep up the heat in a 

 small pipe than it does in a larger one ; it takes less in pro- 

 portion to the radiating surface exposed. Of course, after the 

 fire is out the smaller pipe will cool sooner than the larger one. 

 The motive power, or working effect or force of water, is alike 

 in pipes of all sizes, because as the motive force increases so 

 does resistance. 



It is of great use turning the heated gases over a boiler, 

 because it prevents loss of heat. Soft water should always be 

 used in hot-water apparatus, because it is not so liable to 

 deposit impurities. Generally horticultural boilers gradually 

 become less powerful every year, owing to the increase of 

 sediment or incrustation formed on the inside surfaces. Often 

 the plates are severely burnt from the water being kept away 

 from them through this cause. 



Mr. Peach is mistaken in supposing the rules and laws I 

 advocate are exclusively my own ; on the contrary, they are 

 acknowledged by all scientific men to be correct. 



In deciding on the quantity of pipe required, it is only 

 necessary to put the lemferature of the external air at the 

 very lowest point to which it has ever been known to have 

 fallen, then decide on the quantity of .-pipe by Hood's rule, and 

 it will be found very nearly correct when proved by trial. Mr. 

 Peach says no fixed rule can be correct that is given as above. 

 I am sure we can tell what is the greatest quantity of pipe 

 required to keep a house at a certain temperature when the 

 external air is at its lowest degree of coldness : this is all we 

 require to know on the point, because there should always be 

 sufficient pipe to keep up the temperature required on occa- 

 sions of unusually cold weather. 



As to wind affecting the temperature, if the situation is 

 exposed, it is better to take into account the number of feet of 

 cold air entering by crevices, and add a definite number of feet 

 of pipe to meet the case. Nothing is so unpleasant as to have 

 alterations to make in heating apparatus. This unpleasant 

 necessity is always brought about by working on the guess- 

 work plan, very often called practical. — John Woolfield, 

 Solw, Smethwick. 



HEATING BY FLUES. 

 It is quite cheering to an old gardener to hear that the flue 

 has some advocates amongst practical men ; it brings to recol- 

 lection the labours of bygone days, and also the results of 

 that labour ; for although we did not hear of so many heavy 

 crops of Grapes with the immense bunches we do at the pre- 

 sent day, still there were good Grapes grown in houses heated 

 by flues when proper attention was paid to management and 

 culture ; but not having any gardening periodicals to record 

 the triumphs of the gardener's skill and toil, his labours 

 were not known far from his immediate neighbourhood, but 

 always valued by his employers when superior fruit could be 

 brought to the table. I can recollect fifty years ago of seeing 

 Black Hamburgh Grapes grown to the weight of 4 lbs., and 

 sometimes they reached the weight of C lbs. ; also of houses 

 with a 20-feet rafter producing from 30 to 40 lbs. of fruit on 

 each rafter — a sight worth seeing at the present day, and per- 

 haps not much surpassed by our best growers with the hot- 

 water system. The latter I have no desire to undervalue, nor 

 do I wish to say one word against its usefulness when properly 

 applied, but having had practice with both flues and hot 



