230 THE GARDENER. [May 



the middle of April. This will require earthing up partially about the middle 

 of September. In doing so, commence by putting a band of matting round 

 each plant to prevent the earth from reaching the centre of the plants. At 

 the same time, clear away any loose or broken outside stalks, and all suckers ; 

 break the soil fine with the spade or fork ; and work it in round the plants to 

 the depth of 3 or 4 inches. Give a little dusting of lime to the soil — this 

 will keep worms in check — and always choose a dry time for the operation. 

 If they be growing well, another and a final earthing up may be given some 

 time in October. If they are in double rows, incline the heads towards 

 the centre, so that the tops may be in one straight line. Leave as many 

 leaves above the soil as possible, to continue the growth of the plants. 

 Bearing this in mind, build the earth up as highly as possible, and make the 

 trench with a sharp apex, beating the sides quite firm and smooth. This will 

 assist in throwing off heavy rain; and it will be well to see that water has no 

 chance of standing in the side trenches from which the earth has been dug. 

 Five or six weeks after the final earthing up, the Celery will be fit for use. 

 During hard frost protect the trenches with mats, or straw and mats. For 

 flavouring soups, &c, the green tops are generally used ; and to have a supply 

 all through the spring for this purpose, make a sowing out of doors in May, 

 and transplant in the same way as Lettuce on moderately rich soil — too rich 

 soil causes it to grow rank, and less able to stand severe weather. After it is 

 transplanted it requires nothing in the way of cultivation except water when 

 necessary, and to be kept free from weeds. In winter part of it may be pro- 

 tected with mats or straw, so that it may be easily got when wanted during a 

 storm. Gardener. 



HEATING BY HOT WATER. 



I have read with very great attention the article upon "Heating by Hot 

 "Water," in the February No. of 'The Gardener.' If any one could invent or 

 discover a method by which the necessity for deep stokeholes could be avoided, 

 he, would unquestionably do a service of immense importance to horticulturists 

 and others. But I fear we must look for this somewhere else than in Mr Ham- 

 mond's paper, which only brings forward the ghost of an "old friend with a new 

 face." I do not know whether Mr Hammond is aware of the fact or not, but 

 would he be surprised to find that the method of setting hot-water pipes, recom- 

 mended by him as apparently something new and untried, has been familiar to 

 gardeners and hot-water engineers for a generation ! It is not the case that 

 ' ' engineers and gardeners are agreed upon as being essential to a rapid circulation 

 of the water in pipes" that the boiler should be sunk "below the level of both 

 the flow and return pipes," and giving the pipes "a continuous ascent from the 

 top of the boiler to the furthest points of extension in the building or buildings 

 to be heated." This arrangement of the pipes is often carried out, not because 

 it is considered essential for the rapid circulation of the water, but because, all 

 things considered, it is, in most cases, the best arrangement for other reasons. 

 I can point to very many apparatus throughout the country where the flow- 

 pipe begins to descend immediately after leaving the boiler, and continues to de- 

 scend until it enters the bottom of the boiler as a return. But every one who 

 has had experience knows that, although this works fairly well where there is 

 only one, or at most two, houses to heat, it cannot, even were there any advan- 

 tages to be gained, be carried out in any extensive system. Mr Hammond has 



