314 Scientific Intelligence. [April 



For the purposes of agriculture it is sometimes calcined, which 

 deprives it of its water of crystallization, which in the hydrous gypsum 

 amounts to 2 atoms. This preparation is attended to in France, 

 where the expense of the process is less than in other countries. In 

 England, Germany, &c. it is generally employed in the crude state. 

 The effect which calcination produces, is to render the gypsum more 

 rapid in its operation, though the beneficial effects are less durable. 

 In France it is burned in a kind of lime kiln by means of coal, after 

 being reduced to powder. 



It can be obtained in this state in Gard, for one shilling the 110 

 lbs. avoird., and it costs double the expense in Alais. Extensive 

 natural deposits occur in England in the neighbourhood of the 

 Humber, from whence it is brought to Glasgow and Manchester for 

 the use of the bleachers, who now employ it in considerable quantities. 

 Its purity may be negatively tested by vinegar, which, if it causes no 

 effervescence, shews that there is no carbonate of lime present. If it 

 swells up when water is thrown on it, and then assumes consistence, 

 it is a sign that it has been properly calcined. The best plaster will 

 absorb the greatest quantity of water. It is chiefly on artificial 

 meadows that we observe the best effects from its application, anore 

 especially on clover, lucern, sainfoin, and in general on the legumi- 

 nous tribe of plants possessing large and thick leaves. It has a 

 powerful effect also upon natural meadows which contain much clover, 

 vetches, and other analogous plants ; but upon the grasses the effect 

 of gypsum is trifling. It acts, according to M. Thibaud, by extracting 

 the moisture from the air, and stimulating the vital action of plants. 



It sometimes doubles the product of clover, lucern, and sainfoin. 

 In France it is sowed like corn with the hand, about March or April 

 when the plants are a few inches above the soil, so as to allow the 

 gypsum to fall on the leaves- It should be done previous to rain, 

 but not during the fall of rain, or the existence of wind, or during 

 frost. 



The quantity of gypsum applied to the land must vary of course 

 with the nature of the soil. In the course of fifteen or twenty days 

 the good effects resulting from its use are visible, if circumstances 

 have been favourable. The benefits of one application last for two 

 or three years, so that it is unnecessary to spread it every year. In 

 Gard and Herault sainfoin is principally cultivated for pasture, and 

 seems to thrive well in dry soils, especially in stony calcareous situa- 

 tions. About Alais, for the cultivation of this plant in artificial 

 meadows, the ground is first plowed in November, then again in 

 December, and the seed is sown in the beginning of April. 



In Provence and in the southern parts of Languedoc, where the 

 effects of frost are less dreaded, it is sown in Autumn. The sainfoin 

 thus cultivated in inferior soil affords one or two crops in the year, 

 and lasts for four or six years ; then it is plowed up and corn is sub- 

 stituted for it. It is worthy of remark, that lands which previously 

 could not produce corn, has, by the use of gypsum in the manner 

 described, been able to raise good crops in the midland parts of 

 France. The agriculturists of Alais may procure gypsum from 

 Anduze, Salle, Roehcbelle, and Blanaves. To Drome it mav be 



