72 Forest Club Annual 



until the point -of the hook makes a star on the surface of the 

 water. The height is then read on a scale fastened to the 

 stationary part, the zero point of which corresponds to the 

 bottom of the weir. A vernier is used to read to thousandths. 

 The waterstage register is composed of a drum upon which 

 is placed a specially ruled sheet and the height of the water 

 in the weir as indicated by the float which actuates the drum, 

 is recorded on the sheet by a pen. This pen is held perpen- 

 dicular to the axis of the drum, and moves in a direction 

 parallel to it at a constant rate by the aid of clock-work. 

 In order to free the float from wave action in the basin a still- 

 well should be constructed and the float placed therein. The 

 still-well in this case should be a cement pillar which has a 

 hollow center large enough to admit a float twenty inches in 

 diameter, the water entering the still-well at the 'bottom 

 through a small pipe connecting with the basin. A large float 

 is recommended since it more easily overcomes the friction of 

 the instrument and thus provides for the recording of slight 

 as well as marked changes in the water height. This is true 

 since the large float retains the same relative position with 

 reference to the water height at all times because it so easily 

 operates the drum, while if a small float were used the change 

 in the water height would have to be somewhat greater in 

 order to provide sufficient power to overcome the resistance of 

 the instrument. If it is not found possible to take hook-gage 

 readings in the still-well containing the float, another should 

 be constructed, a six inch iron pipe making a very good one. 

 It is of course very important that streamflow measure- 

 ments be supplemented by records of temperature and of con- 

 ditions controlled by temperature. To gain this end, three 

 meterological stations should be established on each watershed, 

 two of which should be located at the lower end, one on a north 

 slope, the other on a south slope at practically the same eleva- 

 tions, the other at the upper end. During the winter the depth 

 and water equivalent of the snow at different elevations and 

 different conditions of slope and aspect should be carefully 

 measured after each snowfall and in no case should the in- 

 terval between measurements be greater than seven days, even 

 though no snow falls. Then, during the spring thaws, meas- 

 urements should be taken every other day so that the effect 

 of slope, cover, etc., may be determined. 



