THE POSSIBILITIES OF AGRICULTURE. 63 



In such a culture the primitive condition of the soil is of 

 little account, because loam is made out of the old forc- 

 ing beds. The seeds are carefully tried, the seedlings 

 receive proper attention, and there is no fear of drought, 

 because of the variety of crops, the liberal watering with 

 the help of a steam engine, and the stock of plants 

 always kept ready to replace the weakest individuals. 

 Almost each plant is treated individually. 



There prevails, however, with regard to market- 

 gardening, a misunderstanding which it would be well 

 to remove. It is generally supposed that what chiefly 

 attracts market-gardening to the great centres of popu- 

 lation is the market It must have been so ; and so it 

 may be still, but to some extent only. A great number 

 of the Paris maraichers, even of those who have their 

 gardens within the walls of the city and whose main 

 crop consists of vegetables in season, export the whole 

 of their produce to England. What chiefly attracts the 

 gardener to the great cities is stable manure ; and this 

 is not wanted so much for increasing the richness of the 

 soil one-tenth part of the manure used by the French 

 gardeners would do for that purpose but for keeping 

 the soil at a certain temperature. Early vegetables pay 

 best, and in order to obtain early produce not only the 

 air but the soil as well must be warmed ; and that is done 

 by putting great quantities of properly mixed manure 

 into the soil ; its fermentation heats it But it is evident 

 that with the present development of industrial skill, 

 the heating of the soil could be obtained more economi- 

 cally and more easily by hot-water pipes. Consequently, 

 the French gardeners begin more and more to make 

 use of portable pipes, or thermosiphons, provisionally 

 established in the cool frames. This new improvement 

 becomes of general use, and we have the authority of 

 Barral's Dictionnaire d* Agriculture to affirm that it gives 

 excellent results. 



As to the different degrees of fertility of the soil 



