44 



ON THE PRESERVATION OP ZOOLOGICAL SPECIMENS. 



advantages than any other substance; the 

 vessels of which for the larger specimens 

 may he of the capacity of two gallons, of 

 a rectangular shape, approaching to cubi- 

 cal, and more elongated for fishes and rep- 

 tiles; these should be made of green glass 

 as cheaper and more tough; the smaller 

 vials of the capacity of a few ounces, 

 should be of white glass. 



Method of closing the Vessels. — Sound 

 corks and a lute composed in the follow- 

 ing manner: Take common resin and yel- 

 low bees wax, equal weights, and melt 

 them together, then add successive por- 

 tions of colcothar (levigated red oxide of 

 Iron,) till the composition, on dropping a 

 little of it on a plate of glass, has acquired 

 a sufficiency of hardness, then boil the 

 mixture for a quarter of an hour and tem- 

 per it by the addition of common oil of 

 turpentine. Having thus prepared the 

 cement, proceed to close the vessel by se- 

 lecting a proper cork, wiping it dry, and 

 dipping it in the melted cement, drive in 

 the cork thus prepared while the cement 

 is still soft, and pour a sufficient quantity 

 of the same cement over the cork to close 

 completely every orifice; tie down the 

 cork by a cross ligature in the same man- 

 ner as bottles of cider are wired, and cov- 

 er the whole with a piece of cotton or lin- 

 en cloth well soaked in boiling pitch; this 

 for the larger vessels. For the vials, after 

 the cork is put in, invert the vial and dip 

 to the neck in the melted cement three or 

 four times, till the cork is covered with a 

 coating of a sufficient thickness. Cam- 

 phorated alcoholic liquor of strength mere- 

 ly sufficient to preserve the specimens 

 from putrefaction, is preferred to all other 

 substances. The intestines of all animals, 

 and the external mucus of fishes and rep- 

 tiles are to be removed, and the specimens 

 suspended in the liquor by elastic rings or 

 pieces of cork. The cavities previously 

 occupied by the stomach and intestines, is 

 to be filled with sl)'ong camphorated spi- 

 rits. 



From Sir HumphreyJDavy 's Elements of Agricultural 

 Chemistry. 



AGRICULTURAL CHEMISTRY. 



Continued from page 32. 

 The operation of gypsum, it is well 

 known, is extremely capricious in this 



country, and no certain data have hitherto 

 been offered for its application. 



There is, however, good ground for 

 supposing that the subject will be fully 

 elucidated by chemical enquiry. 



Those plants which seem most bene- 

 fitted by its application, are plants which 

 always afibrd it on analysis. Clover, and 

 most of the artificial grasses, contain it; 

 but it exists in very minute quantity only 

 in barley, wheat and turnips. Many peat 

 ashes which are sold at a considerable price 

 consist in a great part of gypsum, with a 

 little iron, and the first seems to be their 

 most active ingredient. I have examined 

 several of the soils to which these ashes 

 are successfully applied, and I have found 

 in theni no sensible quantity of gypsum. 

 In general, cultivated soils contain sufii- 

 cient of this substance for the use of grass- 

 es; in such cases its application cannot be 

 advantageous. For plants only require a 

 certain quantity of manure; an excess may 

 be detrimental and cannot be useful. 



The theory of the operation of alkaline 

 substances, is one of the parts of the che- 

 mistry of agriculture, most simple and 

 distinct. They are found in all plants, and 

 tlierefore may be regarded as amongst 

 their essential ingredients. From their 

 powers of combination likewise, they may 

 be useful in introducing various principles 

 into the sap of vegetables which may be 

 subservient to their nourishment. 



The fixed alkalies which were formerly 

 regarded as elementary bodies, it has been 

 my good fortune to decompose. They 

 consist of pure air, united to highly in- 

 flammable metalic substances; but there is 

 no reason to suppose that they are reduced 

 into their elements in any of the processes 

 of vegetation. 



In this part of the course, I shall dwell 

 at considerable length on the important 

 subject of lime, and I shall be able to of- 

 fer some novel views. 



Slacked lime was used by the Romans 

 for manuring the soil in which fruit trees 

 grew. This we are informed by Pliny. 

 Slarle had been employed by the Brit- 

 ons and the Gauls from the earliest times 

 as a top dressing for land. But the pre- 

 cise period in which burned lime first came 

 into general use in the cultivation of land, 

 is, I believe, unknown. The origin of 

 the application from the early practices is 



