R. Bunsen — Cahrimetric Invest igat it. 



W ith so slight ail agreement between tli.se (lilVnviiT ol~^ 

 CI'-, it ajipearecl to me indispensable to dctenninc. with giv ■ 

 ' : 1 titude than lias hitherto been possible, tin- \ uiiu' .>i S, luv. - 

 - y t>M- the calculation of the constant/). 1 emiilove.l for tiii,- 

 " »c the following method, in which the smuves oi' error 

 . -Ii have made the previous deteniiinatioiis uncertain iia\i' 

 :i entirely avoided : Fig. 6 is a thick walled F-.^hapeW tuhe, 

 "' <iit1icultlj fusible glass, which has been drawn diit at a to a 

 tluek walled point. This is filled with mercurv to A A. aiiu 

 h"th limbs are well boiled out, as is done with haroin.t.r-. 

 '['he })oint a is provided with a small rubber tuh.' thivii.Ll 

 whieh, by means of alternate warming and cooling ol thr ;;'• " 

 tile limb a h, distilled water, free from air, is allowed to . ■■ 

 above the mercury by 6. If this water be boiled idi- hail 

 h'Hir and the rubber tube c be kept under the surface ot wa 

 wliieh has likewise been kept in continual ebullition in a h- a;,- 

 :-;las.s, the space ab will, as soon as the boiling by h is diseontii;- 

 ue«l. till itself completely with perfectly airless water. The 

 rubber tube c is now closed under water by means ot a small 

 glass stopper and the point by a melted off, which may be easily 

 and safely done with the ordinary non-luminous gas flame, with- 

 out the aid of the blowpipe, when the part of the tube wliere it 

 begins to naiTow out into the point is so strongly heated that it 

 IS filled with steam instead of water. If the' apparatus has 

 been weighed before filling with water, and after the filling be 

 weighed again together with the drv point, the weight of the 

 ^yater contained in the instrument will be obtained. The open 

 limb is now completely filled with boiled-out mercury and 

 especially, in order to prevent the adhesion of air bubbles to 

 tlie glass walls, through a long capillary glass tube. If the 

 apparatus be exposed in the open air to "a temperature below 

 f C, an ice tube, corresponding to the glass tube, will be 

 formed which at last closes in different places, and still contains 

 \yuter suiTounded with ice. By the freezing of these last por- 

 tions of water the ice alreadv formed is exposed to a very high 

 pressure, which mav very considerablv alter its specific gravity, 

 niay in fact even burst the glass tube eighty-atmosphere strong, 

 f n order to remove this disadvantage and permit the ice forma- 

 tion to take place, during its entire duration, under the same 

 pressure, it is simplv necessary to sink the whole instrument in 

 sawdust and to expose only the upper part by a to air of a tem- 

 perature below 0° C, after you have previously, in order to pre- 

 vent the effects of abnormal lowering of the freezing point 

 lUber-schruelzung), produced an ice mass by a, which is 

 allowed to dwindle by melting to a small granule. The freez- 

 jng then goes on very regularly from a downward to I and can 

 oe very con\-eniently reo-ulated bv letting the limb containing 



