LITMUS. 175 



Crown afterwards assumed the right to itself, and, at one 

 time, it was considered to be the Queen of Portugal's pin- 

 money;* but it was afterwards ceded to a mercantile company 

 until, by its bad management, the commerce had so much 

 declined that the Government again took it into its own hands 

 in 1790, and now they only allow it to be sent to Lisbon. It 

 grows in the crevices of steep, rocks, in the interior of the 

 islands. The finest is collected in St. Antonio, where it 

 grows in some places so inaccessible as only to be procured 

 by lowering the gatherer down with ropes. But the great con- 

 sumption of it of late years has caused the finest quality of 

 it to become scarce.f 



HENRIETTA. 



What is it chiefly used for? 



MRS. F. 



The English blue broad-cloths are first dyed with Orchill, 

 which gives their peculiar lustre and purple tint, when 

 viewed in a certain light; and, it may also be useful to you 

 to know, that Orchill is manufactured by the Dutch, into a 

 paste called Litmus, of which you will often hear in chemical 

 experiments. When infused in water, or when paper is 

 stained with Litmus, it is employed as the most delicate test 

 for detecting the presence of acids and alkalis; the acid turns 

 it red, the alkali restores it to its original blue color. Orchill 

 is also used for dyeing silk and ribands; but its blue, though 

 beautiful, is perishable. Some writers have endeavored to 

 prove, that the celebrated Tyrian purple was produced from 

 this substance, the lichen being abundant on the Phoenician 

 coast; but we have full evidence to the contrary. 



ESTHER. 

 Might not the purple have been made from Cochineal? 



MRS. F. 

 No; the ancients were unacquainted with this insect, 



* Bowdiob's Madeira. 



f Canary orchill is most esteemed, then that from Madeira, and 

 the Barbary is least valued of all. 



