480 HENEY A. EOWLAND 



A. When a number of Thermometers are sent 

 Comparison between and 40 C. for 3 or 4 thermometers. 



Direct, probable error at each point =TOT $ 20 



Primary Standards, probable error at each point C ^ T ^ T 11 00 

 Secondary Standards, probable error at each point = T f -g- 8 00 



and 100 for 3 or 4 thermometers. 



Direct, probable error at each point = T ^ $25 00 



Primary Standards, probable error at each point = ^-3- 12 00 

 Secondary Standards, probable error at each point = T ^ 9 00 



100 to 250 for 3 or 4 thermometers. 



Direct, probable error at each point y 1 ^ $20 00 



Primary Standards, probable error at each point = y 1 ^ 12 00 

 Secondary Standards, probable error at each point = -^ 9 00 



B. For Single Thermometers 



For single thermometers, the fees for the direct comparisons should 

 be reduced to one-third, and' for the ordinary ones to one-half the 

 above figures. But in this case the thermometer will have to remain 

 here until enough accumulate to fill the comparators. 



Directions for Sending. With each thermometer, send the name of 

 maker, the date when made, purpose for which it is used, and the 

 highest temperature to which it has lately been heated, and the date 

 of such heating, together with the kind of comparison desired, and 

 whether the thermometer is generally used in the horizontal or the 

 vertical position. 



In packing, the thermometer should be placed in a small box, which 

 should again be packed with straw in a larger box. 



The thermometers, both during transit and while here, must be at 

 the owners' risk. Only sufficient fees have been charged to cover the 

 bare cost of the comparison, and we bear the risk of our own standards, 

 which are probably more valuable than any of those which will be sent 

 to us. But every care will be taken, and the probability of an accident 

 is very small. 



We expect soon to be able to make other comparisons, and notice will 

 then be given of the fact by the issue of another circular. 



