i804. On the Atmlyzation of Lime, 45 1 



to the conductor of the farmer's magazine. 



Sir, 



In the ftn<^ures Sir George Mackenzie Is pleafcd to nr.ike on 

 your correl'pondent A. S.'s letter relative to the analyfis of limo 

 and marl, I obfcrve he exprefles a wifh to be informed what wa^ 

 the one half per cent, refidiuim, or alloy, contained in the liiv.e 

 he mentions as belonging to me. As this feems to imply a doubt 

 of the fad:, I confider myfclf called upon to tranfcribe a h'tf^er 

 to me from the Reverend Mr Headrick, well known as a mineral 

 furveyor, and a gentleman of literary merit, as I prefume it was- 

 by a perufal of that letter A. S. obtained his information. I beg 

 leave to remark, that I had Mr Headrick's permilhon to make lull 

 ufe of his name, and that he took the trouble to caufe the work- 

 men give him fair fpecimens of the different ftrata, which he 

 packed up, numbered, and took to Edinburgh with him ; aiul lie 

 aflures me, that he conducted the procefs of analyfis with itrict- 

 nefs and accuracy. 



ExtraB of a Letter from the Reverend Mr Headrick to 

 Mr Lonv of Annfield. Ffefjire. 



* Sir, — I have juft iiniilied the analyfis of your limeftone, 

 imd I confefs that the refult aitonifhes me. It turns out to be the 

 jDureft Itratiiied limeftone that ever paiTed througli my hands. I 

 have met with fome fine fparry lim.eftone, which entirely diflblv- 

 ed in acids, without leaving the fmalleft alloy or refufe ; but all 

 the itratilied limeftone I ever before examined run from 60 to 

 S^per cent. ; and I had even laid down 85 as the maximum of ilra- 

 tified limeltone, becaufe I never fiiw it exceeded, except in one 

 inftance, and that was 90 and fome fractions. 



' Though bare infpeCtion fliowed yours to be very good, I was 

 not prepared to expetl it to be fo pure as it actually is. The ftrata 

 were examined in pairs, as they were put up in the papers, and> 

 as nearly as I could guefs, in the fame relative proportions with 

 the fize of the pieces. The whole was conducted with the ut- 

 moft rigour, and the following is the refult. — No. i. viz. the 

 highefl and thin ftratum below it, contained of carbonate of 

 lime, 944 parts in 100. No. 2. being 3d and 4th ftrata, 98 in 

 100. No. 3. being 5th and 0th ftrata, 99 in ico. No. 4. be^ 

 ing 7th and 8th ftrata, 99, in 100. The laft number containea 

 a fmall fraction more of carbonate of lime, which my inftruments 

 could not meafure, and therefore I gave it againft the ftone. The 

 alloy or refufe, in all, was fine clay. No. 2. &: 3. contained a 

 few particles of fand. All the fpecimens contained a portion 

 of tar and coal culm. I threw the tar out of the calculation, 

 but could not get rid of the culm. In fa6t, thefe ingredients 

 #annot be confidcred as alloy, becaufe they are utterly con- 



v«L. Y. NQ. 20. G g fumed 



