144, ON THE DEPRESSION OF THE FREEZING-POINT 
determination of the reduction factors were available only at 
18°, but as the cell was of glass its value at 0° would not be 
practically different from that at 18°. 
The water bath used in the observations of the conductivity 
at 18° was the same as that described in my former paper. In 
the case of the observations at 0° the bath was modified so that 
the temperature could be kept constant at 0° by means of pieces 
of ice floating in it, while the water was kept continually stirred. 
The ice was prevented from coming in contact with the cell by 
placing around the cell a cylindrical screen of wire gauze 17 em. 
in diameter, and reaching to within 10 em. of the bottom 
of the bath. By the addition or the removal of pieces of 
ice from the salt water, the temperature of the bath could 
easily be kept within one twenty-fifth of a degree for a sufficient 
time to make the measurement of conductivity. The observa- 
tions were made in a basement room of the college, where the 
temperature, during the winter months, was generally below 6°C. 
The thermometer used was graduated to a fiftieth of a centi- 
grade degree and its zero point was determined by the writer. 
Each solution was brought to about 0° before it was placed in 
the cell, and while in the cell successive observations of the 
conductivity were made to insure that the temperature of the 
bath had been taken. 
The method employed for finding the freezing-point of the 
solutions was the same in principle as that proposed by } Loomis 
The size of the protection bath was larger than that used by 
Loomis, and the stirring was done mechanically. . 
The thermometer used was of the Beckmann form. It was 
graduated to a hundredth of a degree, and could be read to a 
thousandth by aid of a small microscope, mounted on an upright 
stand. This thermometer was at a certain place on its stem 
firmly fixed in the cork of the inner freezing-tube (the freezing- 
tubes consisted of an inner and outer tube, the inner containing 
the solution whose freezing-point was measured) so that when 
in position its bulb was within 2 em. of the bottom of the tube. 
1 Phys. Review, 1, 199, 1893 and 9, 257, 1897. 
