7<) DENSITII->> OF OXYGEN AND HYDROCJEN 



The stopcocks Icadiiii,' to the pump could be easily leplaccil Ijy a U-shaped tube 

 filled ^vith mercury wheu tlie jwssage was to be interrupted, and the stopcocks of 

 the globes could be replaced wiih plugs of fusible metal. 



Three orlobes wei'e therefore arranijed as show n in Ficf. 28. At m, n, were 

 plugs of fusible metal closing the tubes which connect the globes to the other appa- 

 ratus. Each globe was weisrhed in aii- and then in water before these tubes were 

 applied, and before the necks of the globes were drawn out ; from which could be 

 computed the solid contents of the globe, or rather the specific gravity of the glass 

 of that globe. The globes were then brought to the form shown in the figure, but 

 with the horizontal tube only a few centimetres long, and wei'e again weighed in 

 air and in water so as to determine their external volume, just as in case of the 

 globes used for oxygen. The weigliing lieing repeated at a dirt'erent temperature 

 the capacities of the globes were thought to be sufficiently well determined. 



The table gives the data of the expej-imeuts together witii the capacities 

 infeii'ed. Weights are corrected for air displaced by objects weighed and by 

 weights used; temperatures are made to correspond with the true scale of a ther- 

 mometer of mercury in Jena normal glass. 



GLOBE. WEIGHT IN AIK. LOSS l.V WATER. lEMPERAI UKE. CAPACITY. 



Grammes. (Irammes. Degrees. Cubic Centimetres. 



A 9169.2 0.32 9170.2 



9164.9 16.10 9J70-3 



9165.2 15.50 9'69-9 



B 18575.4 0.31 '8577-3 



185664 16.05 •85772 



C 16968.9 0.26 16970.7 



16961.1 16.00 16970.9 



A 92279 37224 19.0 372.6 



923-23 37-'-36 17.3 372-6 



Closed 933.29 C(im|)iitecl volume 376-9 



I? "295-93 52280 19.0 523.3 



'295-93 52290 17.3 523.3 



Closed 1303.95 Com|)uted volume 526.5 



C i3''''8.4i 55'92 i';i 552-5 



1368.41 552-02 17.4 552-4 



Closed 1377.1 1 Computed volume 556.0 



From the foregoing dctcrrniiiations of the external volume and s()li<l contents 

 of each globe, we get the capacities as follows: 



Cubic Centimetres. 



Capacity of A 8793.2 



Capacity of U 1 8050. 7 



Capacity of C 164 14.8 



Sum 43258.7 



This is the value to be used for the experiments (^oii another matter) after 

 Jauuary 18tb, But during the experiweots of this series, there were 18 grammes 



