r 133 ] 
follows, that if their Light be fufficiently ftrong, and 
the Air be not hazy, they may be feen in a level 
Country at above 50 Miles Dillance. 
The Obfervations on the fingle Rockets are fuf- 
ficiently confonant to fome Experiments I made 
myfelf about a Fortnight fince : For then I found 
that fevcral fingle Pound Rockets went to various 
Heights between 450 and yoo Yards, the Altitude 
of the higheft being extremely near this laft Number, 
and the Time of their Afcent ufually fhort of 7 '. 
But though from all thefe Trials it fhould feem 
as if good Rockets of ail Sizes had their Heights 
limited between 400 and 600 Yards ; yeti am dif- 
poled to believe, that they may be made to reach 
much greater Diftances. This I in fome degree col- 
left from the Nature of their Compofition, and the: 
ufual imperfect Manner of forming them. 
Nor is this merely Matter of Speculation j for I' 
lately faw a dozen of four Pound Rockets fired 5 the 
greateft Part of which took up near 14" in their 
Afcent, and were totally obfeured in a Cloud near 
9 or 10'' of the Time; fo that the Moment of their 
burfting was only obfervableby a fudden Glimmering 
through the Clouds : And as theie Rockets, during the 
Time they were vifible, were far from moving with a 
languid Motion, I cannot but conceive, that the ex- 
traordinary Time of their Afcent muft have been at- 
tended by a very unufual Rife. 
IX, 
