352 



III ])]aimiiig tlio boxes for experiments. Dr. Steglicli stuflied earefnlly 

 the ])laiis Avliicli liad l>eeu followed by Wolff, Wagner, Hanaiiiaiiii. ami 

 others, and endeavored to improve ui><»n them. In order to make the 

 area and depth of soil suflfteient for normal ji;rowth of a considerable 

 numlDer f)f plants, it was decided to have the boxes 1 meter lon^r, wide, 

 find deep (inside measuic). It was essential that they shonld he very 

 strong and durable and not liable to be cracked by frost or disintegrated 

 by the gases and liquids of the soil and the roots of the plants; and, 

 finally, they must be water-figlit. Zinc it Avas feared would hardly 

 fultill these conditi<»ns. Iron would rust unless it was <-oveied ]»y some 

 enamel, and this was found to be hardly feasible for vessels of the 

 desired size. (Hazed earthenware would V)e excellent, Init the informa- 

 tion from manufacturers as to the feasibility of making such huge 

 vessels was such as to discourage the attempt to get them. A prelimi- 

 nary trial was made with earthenware tiles, Itut they were unsatisfact<try 

 on acj'onnt of the number of Joints Ut be filled. Another trial was made 

 with glass ]>lates set in ccnuMif. The Ixtxes thus c(tnstructe<l and placed 

 in the ground stood the severe w inter of 1S!M)-!M very well, and these 

 ni:ileri;ils were finally selected. The boxes as mad«' are really of cement 

 lined with glass, 'fin* jdates of glass l..i cm. thick were]»ut together in 

 a <'uliical lio\. w liicli serves as a mold, and the cennMit was cast around 

 them, 'file thickness of the cement is about S.7 cm., so that <'ement and 

 glass togethei- make the whole thickness 10 cm. The Joints ot' the glass 

 are <-ai('fully <'o\('red with red h-ad putty to insure more perfect closure. 

 To pniN iilc tor out llow of iliaiuage water and its collection for na-as- 

 urement and analysis, as well as for inflow of watei' for moistening 

 thes(»il from below, an opening is made through both cenuMit and glass 

 close to the bottom on one side, which nniy be called the fiont of the 

 box. Into this oiiening a ulass drainage tube is insertetl horizontally. 

 Inside, on the liottom of the Im»\. a perfoiated semicircular drain tile is 

 laid iVom the opening to the opposite side. The box is sunk in the 

 ground with its bottom resting upon a foundation ot" conciete L'O cm. 

 thick, and its top level with the surface of the surrounding soil. In 

 tilling the lK»\es a layer of giavel is laid upon the bottom, and on this 

 is plae«'d a layer of sand w hi»-h icaches to a height (tf L'O or '_'."» cm. ( )n 

 the sand, w hieli ser\ cs as a per\ ions sultsnil. rests the soil w lii«-h i»'a<lies 

 to the foji of the box. The soil selected tbi- the exi»erinient is cai'cfully 

 sifted and thoroughly mixe(l so that the jKirtions in the ditferent box»'S 

 shall be as similar in character as ]>ossible. 



TwiMify boxes are jdared in four equal rows, w ith i>assages between 

 the tirst and si'cond, and the third an<l fouitli rows. These passages 

 are sunk in the giound to a depth of l.S to l.'.> meters. They are !.."► 

 meters wide and an- faced (ui the sides and «'nds by a brick wall. Each 

 of the two i>assages has a fall of Id cm., allowing water to How to the 

 low t'r end. where it luns through ajtei tares in the wall into a ln'd of gravel 

 outside csju'cially provided to recei\eit. The two passages ojkmi into 



