404 Manufaclurt of H<jts. 



diflblved together in a fufliclent quantity of w.uer, and brought fothe requifite thiclcnefs by 



boiling. ' ' 



This preparation, Timple and eafy as it appears, is not indifferent with regard to the 

 beauty and duration of the work. If it be too tenacious, it renders the (lufTdry and brittle, 

 and after fome months' ufe, a kind of greyifli incruftation is formed on the furface, which 

 alters the texture. . It appeared to me, tliat this effeft was caufed by the gum arabic which 

 is added to the glue. I therefore fought among the plants of our oWn country for a fimple 

 preparation, which might be fubftituied inflead of thefe natural and friable gums. The mu- 

 cU.iglnous principle abounds in a great number of jjlants, and may be eafily extrafted by 

 ebullition ; and a gum may even be formed by evaporation, which preferves its fupplenefs 

 and flexibility. Thcfe confidcrations induced me to recommend, inflead of the ufual pre- 

 paration, a tblution of glue in a deco£lion loaded with the mucilage of linfeed-oil. This 

 preparation has long been ufed with economy in the manufactory, and advantage in the 

 excellence of the work. 



Since that time Citizen Margueron having communicated to me his obfervations on the 

 mucilage which may be extraftcd from the leaves of the horfe-chefnut-tree (marronier 

 A'lnde)., and having afcertaincd liow great a portion of mucous and adhefive matter thefe 

 leaves afford, efpeciaily when the foliation is in its vigour; aftrong deco£lion of thefe leaves 

 has been ufed with much fuccefs to make the preparation with glue. 



There are a great many other native plants, which would be equally proper to afford 

 faftitious gums, and of which the ufe would be very advantageous in the arts. We are at 

 prefent buficd upon this obje£l, and hope in the courfe of time to prefent the refults of our 

 refearches. 



P. S. Since this memoir was written, a philofopher attached to the arts, and who has 

 obferved much, has informed me that oil of vitriol or fulphuric acid is ufed in fome foreign 

 manufadories in the fulling of hats, and that the procefs is confidered as a grea't fecret. I 

 was ignorant of this. The publications I have examined make no mention of it, and the 

 workmen I have confulted had no knowledge of its ufe. Befides which, truth is always 

 new while it continues unknown, and ufeful obfervations require to be repeated in order 

 to make them generally adopted. 



IV. 

 Doubts conctrn'wg the Exigence of a tteiu Earth in the Mineral from New South Wales exa- 



A 



mined iy WedcivOOD in the Tear 1790. 



PORTION of the fame mineral from Sydney Cove in New South Wales as was for- 

 merly analyfed by the late Mr. Wedgwocd, and had been prcfented to M. Haidingcr, Coun- 

 fellor of Mines, by Sir J. Banks, has been lately examined by the celebrated M. Klaproth*. 

 As therefult feems to have inclined this able chemifl torcje£l the new earth of Wedgwood, 

 the fubjed appears fufficiently interefling to admit of being ftated to the public. 



' Bcytrage zur Chcmircben Kcnntnifs dcr Mineral. Koerpcr, b. ii. 



M. Klaproth 



