410 



CAPILLARY ATTRACTION. 





3j 



. n 

 40 



Altitude of 



the fluid. 



Inches. 



Oil of amber 0.343 



Oil of anise seeds 0.342 



Oil of Barbadoestar 0.34-1 



Laudanum 0.340 



Oil of cloves . . . 

 Oil of turpentine 



Oil of lemon 0.333 



Oil of lavender 0.328 



Oil of camomyle 0.327 



Oil of peppermint 0.327 



Oil of sassafras 0.327 



Highland whisky 0.327 



Brandy 



n 



. 0.3; 



45 Oil of ambergrease ..... 0.323 

 enuine oil of juniper . . . 0.321 



Constant Capillary 

 product, Attraction. 



0.0192 

 0.0192 

 0.0191 

 0.0191 

 0.0187 

 0.0187 

 0.0187 

 0.01 84.. 

 0.0184 

 0.0184 

 O.Q184 

 0.0184- 

 0.01 S3 

 0.0183 

 0.0182 

 0.0181 

 0.0180 

 0.0180 

 0.01 IS 

 0.0174- 

 0.0160 

 0.0153 

 0.0112 



Capillary ever, whether the fluid was stationary in consequence 

 Attraction. of any obstruction in the tube, or of an equili- 

 -- - ' brium of the attracting forces, the vessel with the 

 fluid was raised a littl? higher than its former posi- 

 tion, by means of the nut C, and then depressed be- 

 lowit. If the fluid nowrose too, a little above n, and 

 afterwards sunk to p a little below it, so as always to 

 rise and fall with facility and uniformity along with 

 the surface of the fluid in the vessel, it was obvious 

 that it suffered no obstruction in the tube, and that 

 nb was the accurate measure of its height. By sepa- 

 rating the extremity b of the tube from the surface 

 of tfie fluid, the fluid always rises above n ; but upon 

 again bringing them into contact, the flu.d resumes 

 its position at n. If there should be any portion of 

 fluid at the end 5 of the tube, when it u again brought 

 in contact with the fluid surface, the water would 

 rise around it before it had reached the general level, 

 and therefore the height of the fluid, obtained by 

 measuring from the end of the tube, would be too 

 small. In order to avoid this source of error, the in- 

 PLATE CX. dex should have a projecting arm mr. Fig. 7. No. 2. 

 Fig. 7. carrying a screw st, whose sharp point* can be easily Uu ol fcavini 



N. ?. brought on a level with the end b of the tube. When 50 ***** '. 



the extremity /, therefore, which can always be kept *\ * w . lne 



dry, comes in contact with the fluid surface PQ, the rr?, ulp u^r "".''' ' 

 extremity b must also be exactly in the same level, The method of measuring capillary attraction, by 



even though the fluid had already risen around it. ascertaining the altitudes to which different fluids 

 The tube was then cleaned, as formerly, for a sub- wl11 "J: In a S lass * ube 13 n l onl y hable . to " ume ' 

 sequent observation. The results which were thus r us objections, and to much uncertainty in the re- 

 obtained for a great variety of fluids, and with a tube su f lts ! but Applicable only to the single substance 

 0.0561 of an inch in diameter, are given in the fol- of g lass ' ^e are thus left completely in the dark 

 low" Table respecting the action which all the other solids exert 



Altitude of Constant upon fluid substances. 



the fluid. product, 1 order to remedy this defect, an instrument or New in- 



Inches. A X D very general application was some time ago proposed strument 



Water ............ 0.587 0.0327 by Dr Brewster, the object of which was to measure, P ro P se d 



Very hot water ..... / . 0.537 0.0301 upon an optical principle, the diameter of the ele- ^ revv l ter 



Muriatic acid ......... 0.442 0.0248 vated circle of fluid, which any solid raises above formea-' 



Oil of boxwood ....... 0.427 0.0240 the general level. Thus, in Fig. 8. let MNOP be suring ca- 



5 Oil of cassia ......... 0.420 0.0236 the plan of a vessel filled with any fluid A the sec- pillary at- 



Nitrous acid ......... 0.413 0.0232 tion of a solid cylinder of any substance immersed p actlon ' , 



Oil of rapeseed ..... ... 0.404 0.0227 in the fluid and at right angles to its surface, and 



Castor oil ........... 0.403 0.0226 BC the diameter of the circle of fluid, which is ele- 



Nitric acid . . ........ 0.395 0.0222 vated by the action of the solid A. This elevated 



10 Oil of spermaceti ...... 0.392 0.0220 fluid is not terminated abruptly by the circle BC, 



Oil of almonds . . . ..... 0.387 0.0217 but there is obviously a certain distance from A, 



Oil of olives ....... . . 0.387 0.0215 where the ordinate of the curve becomes a perceptible 



Balsam of Peru ....... 0.377 0.0212 quantity, either when examined by the eye or by 



Muriate of antimony .... 0.-873 0.0209 a microscope. The apparent boundary of the circle 



15 Oilof Rhodium ...... . 0.366 0.0205 at B is determined by observing the image of two 



Oil of Pimento ....... 0.361 0.0203 delicate parallel fibres fixed in a frame at D, as seen 



Cajeput oil .......... 0.357 0.0200 by reflection from the surface of the fluid at B, to 



Balsam of Capivi ....... 0.357 0.0200 an eye at F, assisted by a powerful microscope, ad- 



Oil of penny royal ...... 0.355 0.0199 justed to a distance equal to EB-f-BD. When this 



-20 Oil of thyme ........ 0.354 0.0199 image is seen by reflection from any part of the fluid 



Oil of brick, distilled from surface without the circle BC, it will suffer no change 



spermaceti oil ....... 0.354 0.0199 of form ; but when it is seen by reflection from any 



Oil of caraway seeds ..... 0.353 0.0198 portion of the elevated fluid, the fibre. will appear dis- 



Oilofrhue ......... 0.353 0.0198 torted, and they will therefore indicate, by their return 



Oil of spearmint ....... 0.351 0.0197 to a rectilineal form, the apparent termination of the 



25 Balsam of sulphur ...... 0.349 0.0196 circle BD. The same observation is made at D, on 



Oil of sweet fennel seeds . . 0.347 0.0195 the other side of A; and a measure is thus obtained of 



Oil of hyssop ........ 0.347 0.0195 the circle BC, by means of the micrometer screw, by 



Oil of robemary ....... 0.344 0.0193 which the microscope at E, and the frame at D, are 



Oil of bergamot ..... . . 0.343 0,0192 moved along the sides of the vessel. By this instm- 



, 



}: Dr Young found the height of ascent of water and diluted spirit of wine to be as 100 to 64'. 



