180 The Value of Calcium Cycmamide as a Manure 



and 2 gm. CaCOg and covered with untreated filter-paper. This was 

 to imitate the calcium cyanamide as far as possible with the exception 

 that the only gas which could be formed would be ammonia. 



The results are set out in Table I and show clearly that ammonia 

 is the inhibitory cause: the resistance of the seeds appears to be in 

 direct proportion to their size. 



Table I. 



Bell-jar experiments, showing total nu^nber of seeds germinated 

 on each day. 



1 2 .3 4 5 6 7 8 9 10 11 Day 



Lettuce — .'". 9 9 i» 9 9 9 9 9 9 Control 



— ■ — — — — — — — — — Calc. cyanamide +NaOH 



— — — • — — — — — — — do. only 



— — — — — 1 1 1 1 1 ] Ammon. siilph. + CaCOj 



Swede — — 89999999 9 Control 



— — — — — — — — — — • Calc. cyanamide + NaOH 



— — — — — — — — — — do. only 



— — 222222222 Ammon. sulph. + CaCOg 



Wheat _ — _ _ — 2 10 10 10 10 10 Control 



— — — — — — — — — — Calc. cyanamide + NaOH 



— — — — — — — — — — do. only 



— — — — — — 4 4 6 6 8 Ammon. sulph.+CaCOs 



Laboratory Ex'periments. 



A quantitative estimation of the gases evolved when calcium 

 cyanamide is acted upon by water was made, 100 c.c. of water and 

 4-737 gm. calcium cyanamide being used and a week allowed for the 

 action. The results were as follows : 



CO2— 0-001183 gm. = 0-0237 % of calcium cyanamide used. 



H2C2 — trace. 



NH3 — 0-0204 gm. = 0-43 % of calcium cyanamide used. 



The spark was then passed through the residual gases but there 

 was no appreciable change in volume. 



An estimation was also made of the NH3 produced when soil was 

 used in addition to water. Five grams of calcium cyanamide and 100 gm. 

 fine soil and 100 c.c. water were used and one week was allowed. The 

 amount of NH3 formed was 0-1428 gm. or 2-86 % of calcium cyanamide 

 used, i.e. nearly seven times as much as with water alone. 



