304 ' PHUOSOPHICAL TRANSACTIONS. [aNNO I698. 



Saturn by the moon, which happened at 12h. 13m. 55s.: it passed directly 

 under the midst of the moon's disc : clouds hindered the emersion. — Dr. Mullen 

 tried lately an experiment on the famous Irish herb mackenboy, or tithmalus 

 hibernicus, which has been long reported to be so strong a purge, that even the 

 carrying it about in one's clothes is sufficient to produce the effect ; this fabulous 

 story he proved false, by carrying its roots for three days in his pocket, with- 

 out any effect. A quarry of white marble has been lately discovered in the 

 county of Antrim, a specimen of which was brought to us ; it is of an extremely 

 fine grain ; soft at first, but grows very hard afterwards, like Portland stone. 



Concerning Rusma and Alcanna. N° 243, p. 295. 



Dr. Plot showed us some of the Turkish rusma and alcanna, lately received 

 from Mr. Smith, chaplain to the factory at Smyrna, who writes on the use of 

 the rusma as follows : The black earth, which looks as if it were burnt, must be 

 beaten in an iron or marble mortar to a fine powder, and carefully sifted. When 

 you use it, take one part of the powder, and 2 parts of unslaked lime, put 

 these mixed together into a linen rag, which infuse in warm water for the space 

 of a quarter of an hour, or till it becomes of a black colour ; then apply it to 

 the place from whence you would take the hair ; as soon as the hair begins to 

 be loose, the part must be washed with warm water and soap.* The alcanna-|' 

 is the leaf of a plant dried and powdered, which when steeped a night in wine, 

 will dye the nails red, [yellow ?] 



To give Iron a Copper Colour. By Sir Robert SouthiveU, F. R. S. 



N° 243, p. 296. 



Take of small thin copper pieces, cleaned in the fire, gj, of aquafortis §iij ; 

 which being put together in a glass, the copper in 3 or 4 hours will be dissolved ; 

 when cold you may use it, by washing with a feather upon the iron, made clean 

 and smooth, and it will presently take the colour of copper : when it comes off 

 by much rubbing, you may renew it again ; but if you do it twice together, the 

 iron will look black.;}: 



* Rusma is said to be a composition of quicklime and orpiment. It is to the quicklime that its 

 depilatory power is cliiefly to be ascribed. 



f The alcanna of the Turks is said to be prepared from the leaves of the lawsonia inerniis, Linn. 

 It must not be confounded with the European alkanet, which is the root of tlie anchusa linctoria.— 

 ^Linn. 



\ In this experiment, the copper is precipitated in its reguline state, from its solution in aquafortis 

 (nitrous acid) in consequence of the greater affinity of that acid to the iron, a poriiou of which last 

 metal is in conseouence dissolved. 



