Scientific News, &c^ 531 



only, whence it follows that the cubit of the nilometre is within one thoufandth part cf five 

 ninths of the metre, or the eighteen millionth part of the quarter of the meridian. — 'Soc. 

 Philom. No. 27. An. VII. 



Citizen Lalande has communicated to the Iriftftute of France the obfervation and com- 

 putation of the hH oppofition of Mars, and by comparing it with that of 1790, he finds that 

 no more than 58 fecoads are required to be taken from the place of the aphelion of Mars, 

 employed in the lafl: edition of his aftronomy. But he announces the great labours of his 

 nephew, Lefrancais Lalande. 



C. Lalande alfo gave computations of folar eclipfes, and fidereal obfervations obferved for 

 feveral years pad, to determine the pofuions of different places. He places Hamburg at 

 36' 9" from Paris; Cobourg, 34' 30"; Mulheim, 21' ao''; Halle^ jS'a'S''; and Konigfberg,. 



ih 12' 



35" 



Vn the Ufe of the ASiual Cautery in a Difeafeaf the Chefnat-tree, by the'CHJClTAPTAL* 



TJie cbefiHit-tree' forms the only refource of the cultivator in various parts of France, 

 where it is particularly encouraged on account of its utilit}'. This tree lives long, and often 

 gr^ws to an extraordinary fize j but unfortunately its ligneous part <legenerates in feveral 

 circumflances : it foftens, falls into duft, and, in the courfe of time, a cavity is formed in the 

 very heart of the tree, which becomes enlarged by the progrefe of the decompofition ; fo that 

 at lafl: -the. trunk prefents n(?tbi«g but a fliell of bark, which being too feeble to fupport the 

 weight of the branches, or to refift the violence of the winds, can no longer fecure or pro- 

 long its exiftence. By fuch alterations and decompofitions of the ligneous pr.inciple it is, 

 that trees are feen to perifli in a very fhort time, whofe growth have required whole 

 centuries. 



Citizen Chaptal, in his travels through different parts of the republic, and chiefly in the 

 Cevennes and in the department de I'Allier, obferved that the internal part of a great num- 

 ber of chefnut-trees was dug out and burned to a coal all over its furface. The inhabitants 

 explained to him, that this was done to ftop the progrefs of the rottennefs, which would 

 otherwife deflroy the whole tree. , 



When they perceive that this very common and deftruftive difc£tfe begins to make fome 

 progrefs in the chefnut-tree by excavating its trunk, they colle£l heath, and other combuftibie 

 vegetables, and burn them in the very cavity, till the furface is completely converted into a 

 coal : it feldom happens that the tree perifhes by the efFe£l of this operation, and it is always 

 found that this remedy fufpends the progrefs of the decay. It is practifed in the fame man- 

 ner,, and. with fimilar fuccefs,. on the white oak. When we compare the effcdls of the ac- 



^^ tua].' 



t' 



