190 Queries and Answers, 



friable; it easily takes fire, and is indeed used for tinder. When once 

 kindled, it burns for hours, until the whole is consumed, without ever 

 bursting into flame, and however small the part to which the spark of fire 

 has been communicated ; and, what is still more remarkable, the whole 

 mass of wood, even when not ignited, gives a bright light in the dark, equal 

 in intensity, and similar in colour, to that given out by phosphorus. How 

 this light is produced I am at a loss to know. On examining a piece I 

 some time ago picked up, it was evident that it contained neither phospho- 

 rus nor nitre. It is now pretty well ascertained that the glow-worm and 

 other insects of the like kind do not produce their light by means of phos- 

 phorus.* I can find no information respecting touchwood in any books 

 w^hich I have at hand, and I shall be thankful if any of your readers can 

 refer me to any experiments upon it. — B. October, 1830. 



Apocynum andros(S7nifdliu77i. — In mentioning The Journal of a Naturalisty 

 a work from which I have derived much instruction and amusement, I regret 

 that there is any part which can afford opportunity for condemnation, but 

 the account (p. 80. 1st edit.) and engraving of that curious plant, the A^6- 

 cynum androsaemifolium (Fly-catching Dogsbane), is so very incorrect, that 

 I cannot think the author can ever have seen a specimen, much less examined 

 one. From having frequently examined the plant, I can recommend to the 

 notice of your readers the description of it in Curtis' s Botanical Magazine, 

 vol. viii. p. 280., as being very accurate and clear. It is accompanied also 

 with a correct representation of the flower. — W. C. T. Jan. 28. 1830. 



Potato Stone. — Can any of your numerous readers inform me of the 

 scientific name of the potato stone, as it i-^ commonly called, of which 

 such quantities are found in the Mendip Hills, and also the particulai's of 

 their composition ? — W. A. September 18. 1830. 



JEtites or Eagle-stone.-^ Sir, Your correspondent H. D. (Vol. III. 

 p. 484.) has some observations on the v^tites, and asks " where it may 

 be found in this country." The ^tites is the hollow reniform variety of 

 the argillaceous iron-stone. Specimens of this mineral were formerly sold 

 as talismans j and in some parts of this country the midwives keep them 

 about their person, as a sort of charm to further the delivery of their 

 patients. In Greece this is a common notion and universal practice. With 

 respect to the eagle, it is probable that the ^tites may have been found in 

 the nest of that bird, if, as it has been said, they are useful to its digestion. 

 Some accident of the kind may have given rise to the name ; for we cannot 

 imagine that eagles are such old women as the before-mentioned midwives. 

 The following remarks will show that whatever may be the cause of the 

 eagle's affection for this mineral, she need not take a voyage to the East 

 Indies in order to gratify her taste, 



Lemhard (Handbicch der Oryktognosie, 1826, p. 235.) places the " Adler- 

 oder Klapper-stein," (eagle or rattle-stone) in his appendix to his FAsenoxyd 

 Hydraty as the first species of yellowish clay iron-stone, and says that they 

 are often filled with calc spar, brown spar, selenite, or barytes ; and gives 

 . the following list of localities of the species : — 



Goslar, in the Harz ; Qaaerum, near Brunswick ; Tarnowiz, in Silesia ; 

 the country about Bilin and Topliz, in Bohemia ; Meggendorf and Hart- 

 enstein, in Bavaria ; Colebrook Dale, in England ; Dunbar, in Scotland ; 

 Egypt, on the borders of the Desert; Siberia, &c. He also states, that 

 the eagle-stone is found in Italy, in the calcareous strata about Bettola, 

 Torrita, and Monte FoUonico in the country of Siena, and near Orbegne, 

 Fosso del Acqua, &c., where it is known by the name of Pane del Diavolo. 



Phillips {Mineral,, p. 237.) gives, as localities of the clay iron-stone, 



* See an interesting paper published by Carus, Dresden, 1829: " Ue- 

 her das Licht der itaUanischen Leucht/caefer.'* 



