18 



Prof. H. H. Turner. 



and to the west. The test of this is to calculate the contacts 

 for b with the constants given for B, and compare with true values 

 for & ; similarly calculate the contacts for B with the constants 

 given for b and compare with the true values for B. If the errors are 

 of opposite signs, then the curve crosses the envelope, and the con- 

 tact is of the second order. A few experimental calculations of this 

 kind, with the data of ' N.A. Circular, No. 16 ' seem to show, how- 

 ever, that the contact is not generally of the second order, and the 

 approximations are thus subject to the disadvantages above indicated. 



11. Meteorological Observations. Lieut. Crosthwait, R.E., has 

 kindly supplied the following particulars of the meteorological 

 observations : 



They were made from 1898, January 14, to January 24 inclusive, 

 by the following observers : 



Venayek Narayan, Narayan Yishnoo Apte, Govind E/amchandra 

 Bhabhi, and Vishnoo Babaji Garnd. 



The thermometers were attached to a board suspended to the north 

 side of a grass hut, with an overhanging roof, completely shading 

 them from the sun's rays at all times of the day. Height above 

 ground and other dimensions shown in accompanying diagram. 



Gross 

 'Th&toh. 



NORTH 



The situation is open, facing towards the north, on a gently undu- 

 lating plain, about 1500 feet above sea level. The only hills in the 

 neighbourhood are from 2000 3000 feet high, distant about 12 

 miles. 



The following instruments were used : A maximum and minimum 

 thermometer No. 20,443 by Hicks ; a wet and dry bulb No. 38,037 by 

 Negretti and Zambra ; a mountain mercurial barometer, standing on 

 a tripod, No. 1824 by L. Casella. 



