Memoir on the Culture of the A7iatto Tree, &c. 275 



These several glasses are also at the public service for in- 

 spection in our shop in Holborn. 



By making the glasses of the above periscopic spectacles 

 nearly pianos, Dr. Wollaston's principle is destroyed, 

 and my opinion evidently verified : that the nearer a me- 

 niscus approaches to a piano, the more perfect it will be, as 

 the spherical surface for the same focus is diminished, and 

 consequently the aberration. Besides, admitting that there 

 were any advantage derivable from a great obliquity of 

 the axes of the eyes to those of the meniscus-shaped spec- 

 tacle glasses, I would ask. For what reason has man his 

 head moveable? Was it not that he should place his eyes 

 directly before the object to be viewed, and not subject him- 

 self to fallacious ideas of them by an awkward and revolu- 

 tionary squinting? 



From what I have advanced I doubt not of the public de- 

 cision (from a fair comparison of the two kinds of specta- 

 cles) in favour of the established double convex spectacle- 

 glasses ; for 



" Magna est Veritas, et prjevalebit." 



I am, sir. 

 Your respectful humble servant, 



Holborn, April lo. WiLLIAM JONES. 



XLVI. Memoir on the Culture of the Anatto Tree, and the 

 Preparation of Anatto. By C. Lebone*. 



± HAT colouring matter known under the name of anatto 

 is the produce of a tree brought originally from America, 

 and called by botanists Bixa orellana. It approaches near 

 to the family of the tilicB: it rises in good soil to the height 

 of from fifteen to twenty feet, and its branches form a cir- 

 cumference of from nine to twelve feet radius. It flowers 

 at the age of eighteen months; and its flowers, which are 

 attached to a common pedicle, are succeeded by capsules 

 covered with soft points. The seeds are surrounded by an 

 orange-coloured pr.lp, employed in dyeing. The anatto' tree 

 is cultivated in French Guyana; it is multiplied by slips or 

 plants : the former last longer; the latter produce sooner, and 

 live for seven or eight years. They are planted in parallel 

 lines, at a distance which varies from twelve to twenty-four 

 feet, according to the diameter which it is supposed the tree 

 will acquire in the ground destined for it. The aualto trees 



* From the Moniiair. 



S 2 require 



