ides ▁in ▁historical ▁research ▁that ▁have ▁been ▁made ▁here ▁and ▁elsewhere , ▁the ▁quantity ▁of ▁performances ▁and ▁companies ▁in ▁Scotland ▁is ▁not ▁known ▁in ▁much ▁detail . ▁Est ab lish ing ▁the ▁facts ▁is ▁labour - int ensive ▁and ▁problem atic . ▁Dig it isation ▁of ▁newsp apers , ▁mag az ines ▁and ▁other ▁print ▁media ▁helps ▁research ers ▁in ▁some ▁respect s ▁but ▁nation ally ▁this ▁process ▁is ▁still ▁a ▁long ▁way ▁from ▁being ▁complete . ▁Perform ing ▁companies ▁and ▁even ▁the at res ▁have ▁mainly ▁been ▁temporary ▁phen omena ▁and ▁their ▁performance ▁records ▁are ▁almost ▁always ▁lost . ▁The ▁best ▁arch ives ▁are ▁found ▁where ▁companies ▁or ▁ven ues ▁have ▁not ▁only ▁surv ived , ▁but ▁maintained ▁their ▁own ▁records . ▁Prom inent ▁musical ▁examples ▁are ▁in ▁New ▁York ▁the ▁Metropolitan ▁Opera ; ▁and ▁in ▁London ▁the ▁Royal ▁Opera ▁House , ▁Cov ent ▁Garden , ▁and ▁the ▁Royal ▁Albert ▁Hall . ▁ ▁Mem oir s , ▁even ▁those ▁of ▁im pres arios , ▁tend ▁to ▁be ▁long ▁in ▁an ec d ote ▁and ▁short ▁of ▁detail . ▁Little ▁or ▁nothing ▁surv ives ▁of ▁their ▁business ▁records ▁to ▁enable ▁estimates ▁of ▁attend ance , ▁for ▁example . ▁National ▁and ▁local ▁libraries ▁and ▁even ▁special ist ▁arch ives ▁of ▁performing ▁arts ▁material ▁tend ▁to ▁hold ▁only ▁a ▁ha ph az ard ▁hand ful ▁of ▁program mes ▁or ▁other ▁memor abil ia . ▁ ▁For ▁Scotland ▁the ▁task ▁is ▁more ▁challeng ing . ▁Att empt s ▁must ▁therefore ▁be ▁made ▁to ▁identify ▁and ▁build