460 



JOURNAL OF HORTICULTURE AND COTTAGE GA3DENEB. 



[ December 13, 1877. 



will run down the rafter into the house. It is difficult to 

 mate joiners see this, as it involves a little more work and 

 appears so trivial a matter, yet neglect of it will cause all the 

 work to be done a second time, as in my first house. 



Kg. 87. 



It is not essential that the glass be eufc with great exactness, 

 ibough better that it should be. If there be even space to 

 thrust a knife blade between frame and pane I have found the 

 drops of moisture travel easily from one to another, and a 

 little top ventilation is conducive to the health of plant3. 

 Each pane is secured by small indiarubber rollers put on with 

 screws, and three-eighths of an inch thick. The last row of 

 sheets should not rest upon the face-board, but be raised up 

 jby a very thin wedge, just to allow the drip free access to the 

 eaves-spouting, and the grooves of the rafters should die out 

 upon the face-board for the same purpose. The front and 

 doors are glazed in the same way as the roof, and a broken pane 

 can be replaced at any time with great ease. — J. W. Laycock. 



TEMPERATURE AND HUMIDITY OF THE AIR 

 AT DIFFERENT HEIGHTS. 



A memoir on the temperature and humidity of the air at 

 different hours, by Dr. H. E. Hamberg, based on observations 

 ■made by him during the summer of 1875, at heights varying 

 from 2 inches to 22 feet above the ground, was published 

 recently in the " Transactions " of the Royal Society of 

 Sciences at TJpsal. The memoir is a valuable one, and is of 

 interest to more than the mere meteorologist, it being evident 

 that the inquiry is so handled as to bring it into close connec- 

 tion with such difficult questions as convection currents in the 

 ■free atmosphere and the diffusion of vapour through the air. 



In clear weather the temperature of the air nearest the sur- 

 face was lower than that above it, from two to three hours 

 ■before sunset to at least two or three hours after sunrise. At 

 all the six heights the temperature fell to the minimum at the 

 same hour — viz., about 3 ah. ; but while it continued from 

 this time to rise steadily at all the heights, the lowest tem- 

 peratures continued to be observed in the strata nearest the 

 ground till several hours after sunrise. From this remarkable 

 result Dr. Hamberg concludes that the increase of temperature 

 in the lower strata of the air in the early part of the forenoon 

 is not an immediate and direct consequence of the heating of 

 'the ground, but is rather to be attributed to the absorption by 

 the air, or more Btrictly by its aqueous vapour, of the heat 

 received from the sun's rays or reflected from the ground. 



Over uneven ground covered with vegetation the temperature 

 □ear the surface is generally higher over those parts of the 

 field which rise above the general level. Thus even slight 

 elevations ef only 1 or 2 feet have the air immediately resting 

 on them often 2° higher or more, whilst on the other hand 

 a trench or depression 1 or 2 feet below the general level 

 has the air resting on it often 2° or more lower than the air 

 over the level portions of the field, a result of considerable 

 practical importance in agriculture and horticulture. 



The latent heat set free on the formation of dew appears 

 Irom the observations clearly to retard the lowering of the 

 temperature, but not to the extent which might have been 

 expected. When, on the deposition of dew, the temperature 

 of the air near the surface has fallen below 32°, as soon as the 

 dew is coDgealed into hoar frost the temperature of the lowest 

 stratum of air in contact with the ground instantly rises to 

 32° ; but at the same time the temperature of the air higher 

 up steadily remains lower than 32°. 



The absolute humidity of the air on clear nights on which 

 "no dew is deposited decreases from the ground upwards, just 

 as happens during the day; but on the other hand, with dew 

 the humidity is least nearest the ground, and increases with 

 the height ; and this influence of dew in diminishing the 

 humidity extends upwards to at leaBt 22 feet, the height to 

 which the observations were carried. Since his observations 

 clearly show that the absolute humidity begins in the evening, 

 to diminish near the ground before any dew is observed to be 



deposited, and also diminishes at all heights on those nights 

 during which no dew whatever is formed, Dr. Hamberg is of 

 opinion that the diminution of the humidity of the air during 

 night is to be sought for in other physical causes than the 

 deposition of dew. 



Several of the points discussed will doubtless be made sub- 

 jects of further investigation by others. In all cases it is most 

 desirable, indeed absolutely necessary to a critical valuation 

 of the observations, that the authors give woodcuts and de- 

 scriptions of the exact position and mode of protection adopted 

 in the case of each thermometer employed in the observations. 

 For such refined inquiries the method of observation must 

 necessarily be a refined one ; in other words, Buch as will 

 certainly secure the necessary comparability among all the 

 instruments. — (Nature.) 



NOTES AND GLEANINGS. 

 At a general meeting of the Royal Horticultural Society 

 held on Tuesday the 4;h inst., G. T. Clark, Esq., V.P., in the 

 chair, the following candidates were duly elected Fellows — 

 viz., Mrs. Rostock, Lady Cunynghame, Mrs. Going, Mrs. 

 Robert Maxwell, Sir George Meyrick, Bart., R. J. Pettiward, 

 F. J. Smith, Mrs. D. Hall Willats. Mrs. F. Gallup and Mrs. 

 Lewis were admitted guinea members. 



The Veitch Memorial Trustees at a meeting held on 



the 4th inst. confirmed their provisional resolution to place a 

 Veitch memorial medal with a prize of £5 at the disposal of 

 each of the under-mentioned societies for the several subjects 

 specified, it having been ascertained that the exhibitions in 

 1878 of the respective societies will take place at a period of 

 the year when these subjects can be produced. 



Manchester. Jane 7th- — For the best specimen Orchid in bloom. 



York, Jnne 19th — 21st. — For three bunches of Black Hamburgh Grapes. 



Clay Cross, August 13th. — For a dish of Peaches and a dish of Nectarines. 



Hereford. — For twelve cat blooms of the best new Rose sent out within 

 the last five years. 



Exeteb, August 23rd. — For a collection of twelve kinds of vegetables, dis- 

 tinct. 



Brighton, in June. — For one bridal and one ball-room bouquet. 



Woodbrilge, July 11th. — For three stove or greenhouse plants in bloom, 

 distinct. 



Reading, May 23rd. — For three stove or greenhouse plants in bloom, dis- 

 tinct. 



Dublin, Royal Horticultural Society of Ireland, in August. — For three 

 bunches of Muscat of Alexandria Grapes. 



Belfast. — For twelve cut blooms of the best new Rose sent out within the 

 last five years. 



The prizes are to be open to competition amongst ~bona-f.de 

 gentlemen's gardeners eligible to compete at the several Bhows, 

 and the subjects exhibited are in all cases required to display 

 superior cultivation. 



Amongst berry-bearing plants for stove and greenhouse 



decoration during the winter few are more effective than well- 

 grown examples of Abdisia crenulata. The system adopted 

 by those who grow this plant largely and well is to raise seed- 

 lings, and, when large enough, to cut off their tops and strike 

 them in a close well-heated frame or propagating house. 

 When rooted the plants are grown rapidly and close to the 

 glass, and they eventually flower profusely and produce their 

 brilliant berries in great abundance white the plants remain in 

 a dwarf state. They continue ornamental for many months, 

 and are admirable for vase and room decoration. 



The new Zonal Geranium Dr. John Denny, raised by 



J. Sisley of Lyons and exhibited by Mr. Cannell, has, writes a 

 correspondent, quite set at rest the probability of a blue or 

 purple variety being produced, and great honour is due to its 

 distinguished raiser. Besides its prevailing purple colour the 

 base of each petal is bright crimson tinted with oraDge, which 

 gives it a striking appearance ; this, together with its fine 

 trusses, free growth, and shape of blooms, renders it one of 

 the best for pot or house decoration. 



■ The glaucous form of Picea nobilis, a8 exhibited by 



Messrs. W. Paul & Son at the Royal Horticultural Society, is 

 extremely ornamental. We have recently seen the same 

 glaucous form of this fine Conifer in the collection of Mr. 

 Richard Smith at Worcester, and of MesBrs. Cranston & Co. 

 at Hereford. The grafted specimens of this variety are very 

 distinct, and are much more striking than the usual seedling 

 forms of this popular Conifer : both varieties are, however, 

 sufficiently ornamental to be included in all choice collections 

 of ornamental trees. 



It may be useful to note that tbe striking and floriferous 



examples of the old and tiTcciive Fuchsia Dominiana which 



