118 



REMARKS ON DRAINING. 



yellow loam ; and as some may wish to repeat these experiments 

 for their own satisfaction, I shall here state the mode of pro- 

 ceeding and the results. 



Experiment No. L — A square box was made of the form 

 represented by the annexed diagram, 18 inches deep, 11 inches 



wide at top, and 6 inches wide at 

 bottom. It was filled with peat 

 saturated with water to c, forming 

 to that depth (12^- inches) a sort of 

 artificial bog. The box was then 

 filled with water to d. A ther- 

 mometer («) was plunged so that its 

 bulb was within 1£ inch of the 

 bottom. The temperature of the 

 whole mass of peat and water was 

 found to be 39£° Fahrenheit. A 

 gallon of boiling water was then 

 added ; it raised the surface of the 

 water to c. In five minutes the 

 thermometer a rose to 44°, owing to 

 conduction of heat by the ther- 

 mometer tube and its guard. At 

 10 minutes from the introduction of 

 the hot water the thermometer a rose to 46°, and it subsequently 

 rose no higher. Another thermometer (6), dipping under the 

 surface of the water at e, was then introduced ; and the following 

 are the indications of the two thermometers at the respective 

 intervals, reckoning from the time the hot water was supplied : — 



20 m. 



1 h. 30 m. 



2 h. 30 m. 

 12 h. 40 m. 



Thermometer b. 

 . 150° . 

 . 101 



SOi . 

 45 



Thermometer a. 

 . 46° 

 . 45 

 . 42 

 . 40 



The mean temperature of the external air to which the box 

 was exposed during the above period was 42°, the maximum 

 being 47° and the minimum 37°. 



Experiment No. 2. — With the same arrangement as in the 

 preceding case, a gallon of boiling water was introduced above 

 the peat and water, when the thermometer a was at 36° ; in 10 

 minutes it rose to 40°. The cock was then turned for the pur- 

 pose of drainage, which was but slowly effected, and at the end 

 of 20 minutes the thermometer a still indicated 40°, at 25 

 minutes 42°, whilst the thermometer &was 142°. At 30 minutes 



