General Notices. 97 



may write foi" a specimen, or for a scion, or for seeds. Another great ad- 

 vantage of the system is, that by means of the adhesive stamp the sender of 

 a letter may not only pay it, but enclose a stamp in order to pay the answer, 

 and thus make sure of it. For example, A sees a particular variety of turnip 

 seed advertised by B, a seedsman in Aberdeen ; he encloses a shilling and a 

 fourpenny stamp, and begs to have a shiUing's worth of the seed of this 

 turnip by return of post. In short, the sources of benefit and enjoyment 

 of the penny post as a gardening measure are too numerous to describe, even 

 limiting our views to Britain ; but, when we consider that other civilised coun- 

 tries speedily imitate all our leading measures, the benefits which will arise 

 from the penny post may be said to be universal. — Cond. 



Caithness Flagstone. — This promises to be the best flagstone for paths in 

 hot-houses, where stone is used for that purpose, and for the walks of kitchen 

 or flower gardens. Its advantage over every other kind of stone at present 

 used for foot pavements is, that it does not absorb moisture either from the 

 ground beneath, or from the atmosphere above ; in consequence of which, 

 dust or dirt never adheres to it, and therefore any footway in the open air so 

 paved can never get into that disagreeable condition called greasy. The Ar- 

 broath pavement does not absorb moisture from below, but it wears faster 

 than the Yorkshire pavement. The Caithness pavement has one quality 

 M'hich, it must be acknowledged, is rather against it ; that is, it cannot be cut 

 with a chisel, but is sawn on the joints or lines of separation between the 

 laminae. There is a machine at the quarry in Caithness which both saws 

 and polishes. The kitchen and passages of the house of Sir John Robison 

 of Randolph Crescent, Edinburgh, which is a model for every thing relating 

 to arrangement and comfort, are paved with the Caithness stone, and in the 

 lobby it forms a beautiful mosaic work with marble. An account of this house 

 will be given in the Supplement to the Encyclopcedia of Cottage Architecture, 

 which will appear in April next. The Caithness stone may be ordered from 

 John Milne, Esq., Architect, 45. Princes Street, Edinburgh ; and specimens of 

 it may be seen in our garden. — Cond. 



Radiation from Trees. — As a proof of the cold produced in solid sub- 

 stances by radiation in a clear atmosphere. Dr. Guerin has ascertained, as had 

 been previously done by Wells, that the temperature of trees and shrubs is 

 much inferior to that of the air. On January 24. 1827, at seven a. m., the 

 air being 11° 3' cent., the snow adhering to the branches of a cypress and other 

 plants and shrubs was 14° 5' and 15°, that is to say, 3° b' lower than the air. 

 (Jamesoi^ s JEdin. Joiirn., Oct., 1830, p. 376.) 



Calcareous Concretions on the Bottoms of Steam Boilers, S^e. — A simple and 

 very efficacious method is now known of preventing the incrustations in ques- 

 tion ; it is, to add from 26 lb. to 33 lb. of potatoes to the water in a boiler which 

 consumes from 55 lb. to 66 lb. of coals per hour. The boiler may then be 

 employed for twenty or thirty days without being cleaned, and without any 

 fear of a calcareous deposit. After this time the mud must be thrown away, 

 and the same quantity of potatoes again be added. It appears that the fecula, 

 by dissolving in the water, renders this sufficiently viscous to prevent the 

 deposition of the calcareous matter. Flour would produce the same eflTect, and 

 much less of it would be required. A few days after the steam boiler designed 

 to heat the Exchange in Paris was brought into use, it was perceived that 

 there was a hole in the bottom. The fire was extinguished; and it was found, 

 upon emptying the boiler, that the metal was burnt in a place where a rag 

 (chiffon) had been deposited, which had been forgotten when the apparatus 

 v/as set up. (^Foreign Quarterly Review, April, 1829, p. 317.) 



Nurserymen^ s Catalogues. — We are informed by Mr. Lymburn, president of 

 the Kilmarnock Horticultural Society, that Messrs. Allan, Foulds, and Son, 

 Nurserymen, Kilmarnock, have regulated their nomenclature in conformity 

 with that of our Arboretum Britannicum. (R. L. Dec. 18. 1839.) The same 

 has been done with an extensive collection of Ci-atse'gus in the Taunton 



1840. Feb. h 



