506 BROOKLYN BOTANIC GARDEN MEMOIRS 
TABLE I 
Net Absorption by Squash Seedlings from Solutions of Ca(NOs3)2 
Original Concent. of Minimum Concent. of Maximum Net Absorp- 
Solution Solution as tion Calc. as 
Ca(NOs)2 & 1076 Ca(NOs)2 10-6 Ca(NOs)2 1076 
L2Orgkma NOL. ee eae SOLOs STM NOLIN etc eee — 38.0 grm. norm. 
NOc2 we Siete ners AIBYAO). fh! (peadtacircheheanr > Ppigey, “ 
Pi Sete, 5 At eae es Bylo). ae eR AAA STA: = 19.5) i 
Boye ee SiGe aelottrara sete 3250 be Sta hades caer bees afer Anas “ 
ASO. ial tee yaa eRe Ry eg ae Ree. O00 es " 
MIS EG/ e Tad Wa Eee) Ae 29:0) Bote hares T6ol) ay te 
45.5 “ Panto heey ae 26:3 lee FRA ORY ‘ 
62200 os AE Ma eee haG BVA oy Ov Raat hs 230A * 
Oley sl eee eR Oe BAe Oma eM ola 62535 “ 
18236) re AMER aie Roars oe 2916) ntl eee eee RR 153 Omnis yy 
351.8 : MALL Tae se SORE 20 alee SIP Ea tRnido ie B12 7a i 
Sich es) Me Soins ees 47.8 DPM Stn clateeae ATO ae ‘ 
6205 DL eter tie 125.0) 0 TRAE ore 567.6 “ my 
86720) + ep cit oA ey 152.0) Nit ttinet dene: TAS te i 
concentration indicated in any case merely states the net result of 
ion interchange in a given culture stated in terms of such a solution of 
the given salt as would have a like electrical conductivity. 
As the quantity of salt is still further augmented, the unabsorbed 
residue increases, indicating a clear surplus of this constituent. It is 
interesting to note, however, that the unabsorbed residue does not 
increase at a rate parallel with the quantity offered; the absorption 
increasing also though at a lagging rate. The maximum quantity of 
Ca(NO3)2 absorbed by five plants out of a concentration of 867 grm. 
norm. X 10-° is about 714.1 grm. norm. This expressed in weight of 
salt absorbed per seedling would be about 0.0055 grm. This may be 
taken to represent approximately the maximum quantity of Ca(NOs)e 
absorbed by a squash seedling living in darkness in a temperature of 
18° C. during the time required by the seedling to exhaust its available 
reserves. 
CALCIUM SULPHATE 
A somewhat similar experiment was made in which calcium sulphate 
was used, in the hope that we might get some light on the comparative 
effect due to the sulphate and the nitrate anions. A series of 14 cul- 
tures was set up using squash seedlings as before covering a range of 
concentration between distilled water and 830 gram normals of the 
salt in a million liters. The experiment ran from July 12 to 23, 1916. 
A graphic record? of the course of the concentration changes in the 
several cultures is shown in the accompanying diagram (Fig. 2): 
2 In order not to crowd the figure only one curve representing an original 
CaSO, concentration less than 50 grm. norm. is given. 
