Mr. Lubbock on Cask-Gaging. 335 



It seems to me, nevertheless, that uniform instructions, as far 

 as they can be generally applicable, and leaving as little as pos- 

 sible to the judgement, that is, to the guess of the gager, should 

 be carefully drawn up and published for general use, so as to 

 be open to the examination of any one who may question their 

 accuracy. Moreover, if the use of the sliding-rule be per- 

 mitted, whether in the determination of the content or of the 

 ullage of casks, it should be considered merely as a readier 

 method of working ; and it ought not to supersede the con- 

 struction of accurate tables, approved by the Customs and Ex- 

 cise, of which the rule itself would contain the representation, 

 and which might therefore be verified by any one without dif- 

 ficulty. Perhaps the best method would be to calculate the 

 content as in p. 331, employing a mean diameter = h + 



# (b — h) , by means of a table of the logarithms of — , 



3V " J ° 4x255-273' 



or by the lines C and D of the sliding-rule, (See Symons, 

 p. 192,) having previously determined experimentally for va- 

 rious kinds of cask a correction to be applied, in order to im- 

 prove the content so obtained. Accurate tables should also be 

 formed of the ullages of various casks, and in cases of diffi- 

 culty the ullage might be gaged, the cask standing, which is 

 obviously a much simpler problem. 



At present it is not even known how some of the lines on 

 the sliding-rule were originally laid down, or, I believe, for 

 what cask they are intended. Lately an alteration was made in 

 the line marked S L y, by which an obvious inaccuracy was 

 removed ; but this alteration, by which the ullage (vacuity) is 

 diminished, operates disadvantageously to the merchant who 

 pays duty on the liquor. In consequence, the Wine and Spirit 

 Committee requested me to offer them an opinion as to the pro- 

 priety of the change and the accuracy of the method used in 

 determining the ullage. It is obviously impossible to give a 

 complete and satisfactory reply to the latter question, except 

 by means of direct experiments, while we are ignorant what 

 function of the dimensions of the cask the line S L y is in- 

 tended to represent, and without tables of the ullages of va- 

 rious casks with which to compare it. 



No doubt when a general system of public instruction is 

 introduced, with a greater tendency than exists at present to 

 the cultivation of drawing, and of those arts which are most 

 generally useful, the elements of the art of gaging will not be 

 altogether overlooked. 



