150 Prof. D. Mendeleeff. On the Weight of a Cubic [Dec. 5, 



mentioned weight of a cubic inch of air (= 0*4501 A), and as the 

 volume of the weights == 2*298 cubic inches, the correction of the 

 observed weight, in order to obtain the real weight, will be 

 = —1*0343 A ; or if we wish to express this weight in true dolias 

 of a Russian pound, we have to multiply the obtained numbers by 

 1*00000933. The weight so corrected is given in the first column 

 (I) of the following table ; in the second column (II) we find the 

 weight pt of the displaced water, namely, the difference between 

 25579*81 dolias and the numbers of column II, corresponding to the 

 temperature t° R. (column III) . 



In order to find the weight P of water displaced by the cylinder at 

 13J° R., we have evidently to multiply pt by the relation of the 

 specific gravity of water at 13 J° R. (= 0*998890) to the specific 

 gravity at t° and by the relation of the volumes at 13^° R. to the 

 volumes at t° R., the latter relation being equal to 



therefore, 



P = 



1+0*00006796 (t — 13 J) ' 



pt . 0*998890 



[1+0*00006796 (t — 13^)] ' 



The values of P are given in the last (V) column, and in column 

 IV those also of according to formula I. 



Corrected 

 weight of the 

 cylinder in 

 water in dolias. 

 I. 



"Weight of 

 displaced 

 water in 



dolias; p t . 

 II. 



Tempera- 

 ture. 

 Reaumur. 



in. 



Specific 

 gravity of 

 water at 



IV. 



Weight of 

 water displaced 

 at 13£° R. 

 P in dolias. 

 Y. 



1. 7199-31 



18380 -50 



12 -73° 



-999013 



18378 *99 



2. 7199 *30 



18380*51 



12-79 



0-999001 



18379 -14 



3. 7201 -48 



18378-33 



13-65 



-998824 



18379 -20 



4. 7201 *93 



18377 -88 



13 *84 



-998782 



18379 -23 



5. 7202-17 



18377 *64 



13*99 



-998749 



18379 -40 









Mean .... 



18379 -19 dolias 



The numbers of the last column show a slight increase with rising 

 temperature t, which, without doubt, results from the circumstance 

 that the real coefficient of expansion of the cylinder was smaller than 

 ihe accepted (0*00006796 for 1° R.), but in the mean result this error 

 mast disappear, as the extreme temperatures (12*73° and 13*99°) are 

 almost equally distant from 13*33°, and as all the differences P are 

 not considerable.* 



* Supposing that p t = P + a(t — 13^) + 5 (t — 13^) 2 , I have calculated, as did 



