154 THE GARDENER. [April 



more nicely balanced (as much by a judicious allotment of pipes as- 

 by valves) than when pipes from the same boiler are working at 

 different levels. This is a principle far too much ignored in erecting 

 forcing-houses. And we appeal to those who have had experience of 

 forcing-houses at different levels, heated from the same fire, if the 

 attendant evils have not been very conspicuous during the past 

 winter, when hard firing had to be resorted to. 



Small houses, necessarily enclosing a small or thin volume of air r 

 are strongly advocated by some, as capable of being kept at a more 

 equable temperature in cold, fitful, winter weather. A recent writer 

 in a contemporary has laboured hard to prove this ; but his demon- 

 stration appeared to us to be very lame and defective. Our experience, 

 not to speak of anything else, has taught us the very reverse, and we 

 have always found a small narrow structure fluctuate much more 

 sensitively to the influence of cold or sun-heat from without. The 

 principle involved we conceive to be the same as that by which a thin 

 bar of iron, or a thin anything else, cools more quickly than a thicker 

 one. We have for years cut Grapes and gathered Peaches in April 

 from houses only 8 feet wide, and have done the same from much 

 larger bouses, and always found the larger ones more easily dealt with 

 in the matter of steady temperature. And we consider no early 

 vinery or peach-house, to be satisfactory in this respect, should be less 

 than 16 feet wide ; and we shall be disappointed if many early forcers 

 have not verified this in the last severe winter. 



EVERGREEN HERBACEOUS PERENNIALS IN 

 THE PARTERRE. 



There is a very numerous class of hardy perennials with evergreen 

 foliage which may be used in the flower-garden with good effect in 

 summer in conjunction with the usual classes of summer bedding- 

 plants. A more general introduction of the hardy perennial classes of 

 plants with evergreen or persistent leaves with the varied tones of 

 green, grey, white, yellow, and bronze, which they offer at all seasons 

 of the year, would, I think, be a step in the right direction in many 

 cases. Individually, even in pots or in small patches, many of the 

 species which I allude to, and which I will particularise more fully 

 further on, are very attractive at all times ; but in masses of some 

 breadth, or broad lines or bands, they would be still more so. Much 

 of the difficulty that is experienced in mitigating the evils of empty 

 beds and borders in winter would be done away with if suitable hardy 

 plants could be found that may be adapted to the style of bedding-out 

 that finds most favour with the flower-gardening public at present. I 

 think there is no difficulty as to the plants— they are plentiful, and may 



