336 Proceedings of the 



In pointing out the means of producing the desired amelioration in 

 form, the author remarks that, in horses, it is the male which usually 

 transmits more particularly the exterior form, especially that of the 

 lower extremities ; while the internal organs, and the external form 

 of the carcass and crupper of the female, are more generally produced 

 in the young. Hence in endeavouring to improve a native race, it 

 is of more importance to cross it with well-formed stallions than with 

 mares. In copulation, the mare should be at least as high as the 

 horse, and arrived at full development ; and the author proves, from 

 a variety of experiments made both on sheep and horses, that the 

 antiquity of the race exercises considerable influence on the qualities 

 of production ; so that in crossing a native breed by covering indi- 

 genous mares with foreign stallions, it is better to select such mares 

 as have no distinctive mark of race, as the author has himself ex- 

 perienced that the foals of mares of an old Navarroise race have 

 invariably possessed the characteristics of that race, although the dams 

 were covered by a fine Arabian stallion. This observation, which is 

 peculiar to the author, accounts for the jealous care with which the 

 Arabs preserve the pedigree of their mares, and also for the difficulty 

 which has been experienced in deriving as much advantage as had 

 been expected from the importation of Arabian stallions. The advice 

 on the food and health of the animals, with which the memoir con- 

 cludes, does not materially differ from that of other good writers on 

 the subject. The reporters concluded by recommending the memoir 

 as far as it goes (being but a slight sketch) to the warm approbation 

 of the Academy. 



Sand Manure. On the 19th of September, M. Chaptal, in the 

 name of himself and M. Silvestre, read a report on a memoir pre- 

 sented by M. Dutrochet, at the last meeting, and entitled ' Sur le 

 Sable Silicieux comme Substance fertilisante.' The earth forms the 

 support of plants ; air, water, heat, and manure, are the nutritive 

 principles which stimulate the action of their organs. Arable land 

 is generally formed of a mixture of four primitive earths, the various 

 proportions of which constitute the difference of soils, but no one of 

 which would be alone sufficient to constitute good arable land. 

 Chemical analysis has informed us of the proportion in which these 

 earths ought to be mingled in order to constitute a good soil ; and it 

 is of the highest importance to agriculturists that they should avail 

 themselves of this information, in regulating and improving their 

 ground. In the best soils silex is predominant ; in the most fertile 

 of the banks of the Loire, it forms forty-nine per cent. Davy 

 found it sixty per cent, in the best soils of England ; and Giobert 

 mentions that it is as high as seventy-nine per cent, in a very fertile 

 soil in the neighbourhood of Turin. The experiments of M. Du- 

 trochet have confirmed the advantage of employing siliceous sand 

 in certain earths. He covered an argillaceous field with non-effer- 

 vescent pit- sand (sable de mine), and obtained from it much more 



