PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 965 



one glass containing only plain water for comparison. At the end 

 of forty-eight hours, germination was evident in each case ; at the 

 end of the third, fourth, fifth and sixth day, vegetation was most 

 advanced in the three glasses containing respectively plain water, 

 bicarbonate of potash, and sulphite of soda. On the six^i day, 

 the le;ist advanced w^as seen in the o;lasses containing; the three 

 acids ; the hydrochlorine acid glass being behind all. 



In the bicarbonate of potash solution the same number of grains 

 germinated as in plain water, but in the solution of sulphite of 

 soda the number of germinating grains was one-fourth less, although 

 the plants attained the same height as in the plain water. He 

 concluded that bicarbonate of potash was least injurious of all the 

 substances tried ; next was the sulphite of soda ; and next the 

 cjirbouate of soda. The presence of an electric pair did not check 

 germination, but reduced vegetation one-third. In his next expe- 

 riments he included certain organic substances, cane sugar thirty 

 grains, gum thirty grains, glycerine one fluid drachm, and of one 

 vegetable acid (citric) five grains; also, permanganate of potash 

 two grains, nitrate of ammonia twenty grains. A large proportion 

 of sulphite of soda was used, twenty grains, and only one-fourth 

 the quantity of sulphuric acid. At the end of thirteen rather cold 

 days, from the 10th to the 23d of December, it was found that in 

 the citric acid and permanganate of potash solution no roots were 

 formed although the plants had grown an inch high. At the end 

 of a month the roots in the sugar cane solution were only an inch 

 in length, while those in the gum and glycerine solutions had 

 reached the very bottom of the vessels. Vegetation was as active 

 in the last three named solutions as in pure water, and some of 

 the plants in the gum solution were fully one-half higher than in 

 the other three liquids. The pkints in the solutions of sulphite of 

 soda and nitrate of ammonia were very slightly in advance of 

 those in plain water. 



Ventilation of Ice-bound Fish Ponds. 

 Mr. C. Tomlinson, in The London Chemical N'ews, after allud- 

 ing to the common practice of breaking the ice on a fish-pond to 

 supply the fish with air, raises the question how are natural lakes 

 and ponds supplied with air ? On consulting books he was sur- 

 prised to find a contradiction on the part of naturalists of repute. 

 Swainson ascribed the loss of thirty or forty fine tench, in a pond 

 covered with unbroken ice, to the extreme cold. In opposition to 



