7. 



and of & 5 ft. glass tube snd attaching It at the and of the air Una. Mercury 

 ass than poursd in tube until a prsuaire *%e reach ji »t which »ir would 



babble through the Jars at the desired rata. 



Dally Ojj deteralnotlonb were aade on the water from g »eh jar 

 by the Pinkie r eat hod. Seaples f '*e determinations were collected by 



introducing a Powera*oa.*plln;7; bottle (Power* 1918) between two jars and allowing 

 the aster to siphon through it fifteen minutes. 



Aa hae been aantiojend above, the oxygen-fro<* water from the boiler 

 ie strongly alkaline. Intra neutral water watt desired, thle was reraadiad by 

 aesns of the acidulator (upper left hand of fig. l) a-.ich cone lets of a twelve - 

 liter aepirated bottle pl*oed in a large earthenware sdlk pen, with the u?per 

 opening corked securely. T'te acid In ia* pit ., HI timot at %ht loval of the 

 top of t'.e lower opening in IIm bottle, thua giving a constant pressure in the 

 siphon which is drawn to a- capillary tube aft the diets! end. 1 floir of 



the acii is rag 1a 3i*e si tat capillary tube. ?ha acid drops froa 



the oiphon i M separwtory funnel, rough anion it p-iseea to tha bottaa 



of the ten-liter aixic£ bottle, vhare it la thoroughly mixed with the water 

 before enter 'riaental Jara; 1 ,'l '* H3SO4 was uae-i. Vat aoiJity of 



*ater could bo ro;: by 00 • the atMkbtf of drop* of i»ci* per ainute 



•sn-i ragalatiag tin flow of water throngs taa aisiag tottlt aaaoTdlagly* 



In some preliain-iry aaaerlaaata, ordinarily distills! water 

 obtain* 1 froa the Daaartaaat of Chemistry ffas used. This water ie condensed in 

 a copper oondenser and paaaes through blocked in tin pipes. It was found not 

 only to be very toxic to tadpoles but to vary In Its effect froa day to lay so 

 that tadpoles eiight live sever-*! days in water taken froua one bottle and die 

 in a few hours in water tnkan froa another. fho saae water redictillsd in glass 



