NOTES AND ABSTRACTS. 



299 



When sodium bi-carbonate is added to weak solutions of copper 

 sulphate, the basic carbonate 5Cu03C0 2 is produced, the precipitate 

 being contaminated with sodium carbonate and basic sulphate, especially 

 when excess of copper is present. When concentrated solutions are used 

 C0 2 is evolved, and the precipitate formed redissolves. 



Perhaps the most interesting part of the investigation is that of the 

 cupri- carbonates, a name given by the author to the hitherto uninvesti- 

 gated compounds produced by the solution of certain of the basic 

 carbonates in sodium carbonate. 



These were produced by reacting with mixed solutions of carbonate 

 and bi-carbonate of soda upon copper sulphate, and in these the copper 

 becomes electro-negative, taking its place as a constituent of the acid 

 radicle ; in this state it does not respond to the usual tests for copper, 

 such as potassium ferrocyanide (prussiate of potash). 



The normal carbonate of copper has not yet been isolated. — W. A. V. 



Crambe COrdifolia. By S. Mottet (Le Jard, xxiii. 527, p. 37 ; 

 February 5, 1909 ; 1 fig.). — The genus Crambe is little known as an 

 ornamental plant ; C. maritime/, (the seakale) is a favourite vegetable ; 

 G. tatarica is also edible, but is less inviting ; G. juncea, and lastly 

 C. cordifolia. This handsome plant is native in the Caucasus and 

 Siberia ; hence it is perfectly hardy, and might well be planted out in parks 

 and shrubberies. The leaves are shiny and dark green, about 18 inches 

 across. The flowers are white and sweet-scented, very small, but arranged 

 in long heads or sprays like Spiraea Aruncus. These plumes are easily 

 blown down and broken, so it is well to tie them to a stake as soon as 

 developed. The plant prefers a sunny aspect, and will flower ten years or 

 more without degenerating. It may be divided in spring. — F. A. W. 



Crataegus, New Species of. By F. Ramaley (Bot. Gaz. vol. xlvi. 

 pp. 381-384 ; November 1908 ; 2 figs.). — Two new species are described 

 from Colorado, viz. C. Doddsii and C. coloradoides. — G. F. S.-E. 



Cress, Cultivation of. By M. Houssy (Le Jard. xxiii. 525, p. 10 ; 

 January 5, 1909). — Watercress is so easily cultivated, and so lucrative, 

 seeing that it only requires a ditch some 50-60 cm. deep, and 50-60 metres 

 long, that it is a pity more use is not made of it for the English market. 

 Clay soil is the best, as a moderate flow of water from Sume neighbouring 

 spring will then provide sufficient to moisten the trenches ; in light or 

 sandy soil it is necessary to line the ditches, which adds to the cost of 

 production. A cress ditch can be reaped every three months ; the plants 

 are best renewed every year. Another method is to saw a barrel in half, 

 and fill the tubs with water, covered with a trellis of wicker or galvanized 

 iron. Plant cress on the top of the meshes. It is not necessary to 

 change the water, as it remains good from May to November. Fertilize 

 with ammonium sulphate every three weeks. This should be pulverized 

 and spread on the water, or dissolved in water and poured in. Again, 

 the tubs may be cut down to 50 cm. from the ground and filled with 

 earth, leaving a drain pipe in the centre, down which water is poured 

 daily. Another plan is to pave a bed of soil with the inverted bottoms 



x 2 



