32 SUBSTIT'UTE FOR GUM-ARABIC. 



Inftruftjons Care (hoiild be taken, and advice given, tliat Ihe wood^ 



[he'i^'i'tfand ^^^uld not be left deftitute of the roots ; and it would be ad- 

 fecuring their vifeable to offer premiums for the cultivating the roots and 

 growth. offsets, as they are very increafing. By fuch means a con- 



ftant fupply may be had, if the roots anfwer the intended 

 purpofes. 



I do not prefume to offer any thing refpe6ting the mode in 

 which the Society may think proper to divulge the difcovery, 

 and promote the ufe of thefe roots; but I imagine, that if the 

 roots are bruifed and ufed freth, they would anfwer Ihe purpofe 

 better than when dried ajid powdered ; and as it is now a 

 proper time of the year for taking them up, and will continue 

 to be fo for two months, I wifti that the difcovery may be made 

 known as foon as poffible. 



I have fent you fpecimens both of the dried roots and pow- 

 der, that they may be feen at the Society's rooms, by the 

 calico-printers. What I have done have been fcorched a 

 little in drying; but the colour would be much better, if proper 

 care was taken in drying them. 

 I am. Sir, 



Your mofl obedient Servant, 

 Lime-Street, THOMAS WILLIS. 



March 17, 1802. 



To John Baker t Efq. one of the Mem- 

 bers of the Society of Arts, S^c. 



From the trials made before the commrttee with this powder, 

 with hot and cold water, from famples of the printed cotton 

 produced which had been printed therewith inflead of gum 

 fenegal, and from experiments made in Manchefler, it ap- 

 pears that the hyacinthus non fcrlptus may, in fiiany cafes, be 

 found a ufeful fubftitute for gum-arabic. 



A Memoir 



