TRANSACTIONS OF THE SECTIONS. 33 



garded as having yielded the same results. In referring to these experiments, it 

 must he remembered that the season of 1864 was exceptionally dry, though the 

 drought was not so great in Scotland as it was in England. The results obtained, 

 however, are valuable as representing the produce obtainable in a dry season ; and 

 as a similar series of field experiments are being made this year in the same district, 

 an opportunity will be obtained for contrasting the results for both years. 



On Esparto Fibre, or SpanisJi Grass, and its Employment in the Manufacture 

 of Paper. By Dr. Stevenson Macadam, F.B.S.E., F.O.S. 

 During the last three years large quantities of a grass obtained from Spain have 

 been employed in this country in the manufacture of paper. Delivered in Great 

 Britain, it costs about £5 10s! to £6 per ton. The recent high price of rags has 

 caused a demand for esparto fibre ; and should it continue, other countries, as Bar- 

 bary, which yield the same grass will no doubt contribute largely to the supply. 

 The chemical composition of an average sample is — moisture, 9'62; oil, 1"23 

 albuminous compounds, 5-46; ligneous fibre, 56-28; starch, gum, and sugar, 

 22-37 ; ash, 504. In the manufacture into paper, the material, first carefully 

 cleaned, is subjected to the action of caustic soda. The fibre, however, is rather 

 short in nature, and hence paper entirely made of it is extremely liable to tear. It 

 is customary, therefore, to give strength by mixing the pulp from esparto fibre with 

 the pulp from rags, commonly in the proportion of equal parts. The paper so ma- 

 nufactured is largely employed as a printing paper, and the majority of the Scotch 

 newspapers are now printed on it. The spent soda liquor, being of a caustic na- 

 ture, 13 highly pernicious and destructive to fish, when it is run directly into a fish- 

 ing-stream ; even if diluted to the extent of many times its own volume, the liquid 

 possesses the power of killing them within a few hours. Two plans have been 

 suggested and put in operation for the arrestment, more or less completely, of the 

 soda liquor. The first, the boiling down the ley, heating the residue with carbo- 

 naceous matter, such as fine coal or sawdust, and the recovery of the soda from 

 the calcined mass ; the second, the reception of the liquor in large open cesspools, 

 where it may percolate through the soil. Both plans have been successful. 



On Crystals of Melaconite, and on Tenorite. By Professor Maskeltne, M.A. 



Professor Maskelyne described crystals of oxide of copper (melaconite) that had 

 recently been found by Mr. Tailing of Lostwithiel. They are brilliant in lustre 

 and of a dark steel-grey colour, and occur in a chloritic vein-stone. Their crystal- 

 lography presents considerable difficulty from the corrugated and uneven character 

 of certain of the faces, and the incompleteness of the crystals. But measurements 

 made on three or four selected crystals establish the oblique system as that of the 

 mineral. 



The planes met with are (100)«, (001)e, (0 1 1) (1 1 1) (1 1 1) (6 1) (6 1 1), and 

 the crystallographic constants of the mineral are given by the values of the para- 

 meters, a:b:c = 1-4902 : 1 : 1-3604, 



and of the inclination of normals to c, a, viz. 001, 100 = 80° 28'. 



The fracture is generally conchoidal, and cleavages exist parallel to (1 1 1) and 

 (001), the latter a facile one. The crystals are generally twinned ; one twin plane 

 is 100. 



The hardness is a little above 4, the specific gravity = 5-82527. 



The mineral Tenorite, the form of cupric oxide, found in certain old lavas of 

 Vesuvius consists in fine ribbon-like fibres, transparent under the microscope, and 

 presenting feather-like twinned aggregates of laminated crystals. The individual 

 crystals cleave readily with an angle of a little more than 72°. 



They present the interesting property of absorbing one of the polarized rays of a 

 beam of light traversing them, just as does a plate of tourmaline cut parallel to its 

 optic axis. It is not impossible that Tenorite may represent the melaconite crystal 

 in laminae parallel to 100. 



The sooty blackness of cupric oxide in its powdered and more massive form may 

 1865. 3 



