196 F. B. GUTHRIE AND R. HELMS. 



No. 24 germination weak, plants very puny, had died by 



July 24th. 

 Nos. 25 and 26 did not germinate. 



Pots 25 and 26 were resown in No. 2 soil on July 3rd 

 with '2 and *4 per cent. Na 2 Oo 3 respectively. 



In pot 25, containing '2 per cent. Na 2 Oo 3 , the seeds germin- 

 ated well and the plants were growing well on July 24th 

 and August 26th, the heads were forming Oct. 8th. In 

 the pot containing '4 per cent. Na 2 Oo 3 germination was 

 much affected, and the plants were very feeble on July 24th 

 and had all died by August 26th. In the other pot con- 

 taining *30°/° Na 2 Co 3 germination had been retarded and the 

 plants were less vigorous on August 26th. 



The conclusions drawn are the following : — Quantities 

 of Na 2 Oo 3 up to *20 per cent, of the soil do not affect the 

 growth of wheat in any way. With *30 per cent. Na 2 Co 3 

 in the soil germination is affected, with *40 per cent, the 

 germination is much affected and the plants die. *3 per 

 cent, can therefore be regarded as the limit of endurance. 



Experiments tvith ammonium sulphocyanide. 

 Ammonium sulphocyanide is occasionally present in 

 sulphate of ammonia, particularly in the product obtained 

 from the commercial liquor of the gas-works. We have 

 never come across it in any samples of sulphate of ammonia 

 manufactured locally, but its poisonous action is so much 

 greater than that of the substances just discussed, thatfit 

 appeared a matter of some importance to ascertain how 

 much plants can stand. 



The following pots were prepared and filled with soiL 

 No. 1 and manured and sown as before on June 3rd. 

 Pot 28, 0-01 per cent. NH 4 ONS 

 „ 29, 0-05 

 „ 30, 0-10 

 » 31, 0*50 



