Moss — On an Irish Specimen of Dopplerite. 99 



modification of Tacke's method : — An accurately weighed quantity 

 of the original moist substance, about 10 grammes in each case, 

 was reduced to a fine pulp in a mortar,, with the addition of 

 water, and washed into a 200 c.c. flask; the total quantity 

 of water employed was about 50 c.c. The flask was then 

 closed with a cork through which two tubes pass, one tube 

 reaches to the bottom of the flask, and is connected with a hydrogen 

 generating apparatus. The other tube extends only a little below 

 the cork, and communicates with the lower orifice of a double 

 surface condenser ; the upper orifice of the condenser is connected 

 with a OaCl 2 tube, and a weighed soda-lime tube. With this 

 arrangement, and a supply of cold condensing water, it is possible 

 to pass a current of hydrogen through the boiling contents of the 

 flask for several hours without carrying over more water vapour 

 than a short CaCl 2 tube is capable of removing. The tube through 

 which the hydrogen enters the flask is made in two pieces ; the 

 lower piece is a thistle-tube, to which the upper piece acts 

 as a stopper. This arrangement enables one to add water, in 

 which calcium carbonate is suspended, to the contents of the flask 

 without admitting air or allowing hydrogen to escape. The 

 hydrogen, before it entered the flask, was passed through a solution 

 of potassium hydroxide in a Pettenkofer absorption tube at the 

 rate of about two litres per hour. 



The application of this method to the Sluggan dopplerite and 

 peat gave the following results : — Dopplerite, 10*05 grammes of 

 the moist substance containing 1-413 gramme of dry matter 

 liberated in three hours at the ordinary temperature 0-0237 

 gramme C0 2 . On boiling for three hours a further quantity of C0 2 

 weighing 0-0411 gramme was evolved, making a total of 0-0648 

 gramme C0 2 . This corresponds to 4-58 parts of C0 2 for every 

 100 parts of dry matter. Peat, 10*19 grammes containing 1*134 

 gramme of dry matter, liberated 0-0168 gramme C0 2 in three 

 hours at the ordinary temperature, and -0260 gramme on boiling, 

 making a total of 0*0428 gramme, corresponding to 3*77 parts C0 2 

 for every 100 parts of dry matter. On the assumptions already 

 referred to these figures show that the Sluggan dopplerite in the 

 dry state contains 72*87 per cent, of humic acid, while the peat 

 with which it is immediately associated contains 59*98 per cent, 

 of humic acid. If instead of Mayer's formula for humic acid we 



