222 The Plant World. 



total amount of absorption. By interpolation it is estimated 

 to have been about 5,500 cc. for the period of 145 days. During 

 the last 35 days the absorption amounted to 520 cc, giving a 

 round total of something like 6,000 cc. for the 180 days. 



The modeling clay was rolled back once, for four days, 

 after the experiment had been in operation for two weeks, after 

 this it was replaced and allowed to remain until the end. The 

 cup had to be refilled twice, once when the reservoir had been 

 allowed to becom,e empty and again when the graduate, used as 

 a reservoir, had been accidentally broken. 



The plants grew rapidly, better than those watered in the 

 usual way. Two of them showed an increase in height of 62 and 

 59 cm. respectively. The original height was 14 en. in each of 

 these two cases. One plant had been in bloom 69 days, the sec- 

 ond, 57 days, at the end of the experiment. A few flowers could 

 still be' seen on IMay 18. The third plant had lost its primary 

 growing point and had three branches. One of these elongated, 

 in 145 days, from 15 cm. to 28 cm. in length. None of the 

 branches of this plant had yet bloomed at the end of the experi- 

 ment. The appearance of the culture at the end of 104 days is 

 shown in Fig. 1. 



The excellent growth made by these plants, under conditions 

 which cut off the usual supply of air to the soil, seems remark- 

 able in the face of what is usually held in this connection. But 

 with such meagre data at hand, it is sufficient to state here that 

 they grew vigorously for 161 days without other appreciable 

 supply of oxygen to the roots than by way of the water in tube 

 and cup and by way of the aerial parts of the plants. The plants 

 were watered through the cup for 180 days, and were apparently 

 as healthy at the end of that time as at the beginning. Two of 

 them had nearly completed their life cycle and were practically 

 at the end of the period of blooming on May 18. 



In the experiments with Vicia Jaha, five 6-inch pots were 

 used, four of these being supplied with the automatic watering 

 device, and the fifth being left in the gardener's care and watered 

 daily in the ordinary way. Pot 1 was completely sealed, as in the 

 experiment with Coleus; pot II was paraffined but the soil sur- 

 face was not covered; pot III was sealed over the soil surface with 

 modeling clay but was not paraffined; pot IV was left unsealed. 



