210 ConJiruSlion of an Eeommical Laboratory. 



In the fecond volume of the memoirs of the ancient academy of Dijon, I gave a defcrip- 

 tion of a box containing a Icind of portable laboratory, conipofed of a lamp with three wicks, 

 difpofed in the figure of an equilateral triangle, to form an internal current of air, with fup- 

 ports for the different veffels of digeftion, diftiilation, evaporation, &c. I made a folutionr. 

 of fjjver with common aqua fortis and the metal in an alloyed ftate, which anfwered very- 

 well as a re-agent, without having occafidn for any other utenfils but this box and apothecary's, 

 phials, which are every where to be found. A number of thcfe boxes have been fitted op 

 by Citizen Dumoutier, more particularly for travellers, and I have reafon to think that they 

 have proved ufeful. But this apparatus mud neceffarily be confined In. 'as application, and 

 is difTerent from the objecl I purpofe to defcribe at prcfent. 



Ten years ago, I conftrufted a lamp, on the principles of Citizen Argand, with three con, 

 centric circular wicks, each having an interior and exterior current of air. The effeiSl fur* 

 pafled my expectations with regard to the intenfity of the heat; but it was difficult to pre- 

 vent the deftruftion of the hard folder round the wicks ;. and the glafs retorts were frequently 

 melted at the bottom, and disfigured. It may eafily be imagined, that the quantity of oil con- 

 fumed \yas confiderable ; and as it could not be ufed at the fame time for giving light, it hadj 

 to fay the truth, no more than a remote application to the objefl.' of the prefentcommuni- 

 •ation. 



A Ihort time afterwards it occurred to me, to fubftitutCi inftead of the glafs chimney of 

 Argand's lamp, a cylinder of copper with an indented part or ledge a few millimetres * above 

 the flame, to perform the office of the indented chimney of glafs, and by that means to 

 render it practicable to raife the wiek to a certain height without fmoking. This 

 cylindfeF has three branches like a chaffing-dilh. By this apparatus two or three decilitres 

 of water (about half an Englifll wine pint) may be brought to boil in a copper or glafs veflel 

 in about fix or feven minutes. It has ferved, and 1 ftill ufe it, for a number of operations ;, 

 but it was not till' after I had obferved the degree of heat obtained from the kmp in its ordi- 

 nary ftate, and' particularly fince \ have fubftituted inftead of the metallic tube a chimney of 

 glafs cut off at the length of three centimeti-es (rather more than one Englifh inch) abova 

 the contraction, that f perceived all the advantages i^t was capable of affording; and that by 

 means of a moveable fnpport for the reception of the different veffels, which may be fixed at 

 pleafure by a thumb-fcrew, this lamp furnace, at the fame- time that it gives light, and con- 

 fequently without any additional expence, may with facility be ufed for almoft every one of 

 the operations of chemiftry; fuch as digeftions, folutions, cryftaHizations, concentrations j 

 the rcClification of acids; diflillations on the fand-bath, or by the naked fire; incinerations 

 of the nioft refraftcry refidues; analyfes with the pneumatic apparatus, or of minerals by the 

 (aline fufion, &c. &c. I have not hitherto met with any exception but for complete vitri- 

 fications and cupellations ; for even the diftillations^todrynefs may be performed with fome 

 precautions, fuch as that of transferring the matter into a fmall retort blown by the ena- 

 meller's lamp, and placing its bottom on a little fand-bath in a thin metallic difli. 



The fupport, here mentioned, is fimply a copper ring eight centimetres (3,15 inch)in 

 diameter, which is raifed or lowered by Aiding on a ftem of the fame metal. It is defcribed 

 in the memoirs of the academy of Dijon as part of the portable laboratory; for which reafon; 



.• for the value of the new mcafures and weights of France, fee Philof. Journal, 1.33a. 



