182 HOW CROPS GROW. 
list of necessary ingredients of maize, and from not yet 
fully described experiments doubts that it is necessary for 
buckwheat. 
Leydhecker, in a more recent investigation, has come to 
the same conclusions as Nobbe & Siegert, regarding the 
indispensableness of chlorine to the perfection of buck- 
wheat. (Vs. S¢., VIII, 177.) 
From a series of experiments in water-culture, Birner 
& Lucanus, (Vs. St, VIII, 160,) conclude that chlorine 
is not indispensable to the oat-plant, and has no specific 
effect on the production of its fruit. Chloride of potassium 
increased the weight of the crop, chloride of sodium gave 
a larger development of foliage and stem, chloride of mag- 
nesium was positively deleterious, under the conditions 
of their trials. 
Lucanus, (Vs. Sé., VII, 363-71,) raised clover by wa- 
ter-culture without chlorine, the crop, (dry,) weighing in 
the most successful experiments 240 times as much as the 
seed. Addition of chlorine gave no better result. 
Nobbe, (notes to above paper,) has produced normally 
developed vetch and pea plants, but only in solutions con- 
taining chlorine. Knop, still more recently, (Lehrbuch 
der Agricultur-Chemie, p. 615,) gives his reasons for not 
crediting the justness of the conclusions of Nobbe & 
Siegert and Leydhecker. 
Until further more decisive results are reached, we are 
warranted in adopting, with regard to chlorine as related 
to agricultural plants, the following conclusions, viz.: 
1. Chlorine is never totally absent. 
2. If indispensable, but a minute amount is requisite in 
case of the cereals and clover. 
3. Buckwheat, vetches, and perhaps peas, require a not 
inconsiderable amount of chlorine for full development. 
4. The foliage and succulent parts may include a con- 
siderable quantity of chlorine that is not indispensable to 
the life of the plant. 
