[ ] 
hazy, which render’d it impoffible for them to be 
feen to any confiderable Diftance. 
It King obferv’d in thefe Trials, that the larged 
of rhe Rockers, which were about 2 Inches and a 
half in Di meter, rofe the highed, Mr. Robins in- 
tended to have made fome more Experiments, in order 
to a farther Difcovery what fiz’d Rockets would rife 
highed: But his Engagements with the Eaft India 
Company preventing him, Mr. Samuel Da Cofta 
late of ‘Devonfhire- Square, a Gentleman of an ex- 
traordinary Genius in Mechanics, and indefatigable 
in the Application, Mr. Banks, a Gentleman who 
had for many Years practis'd making Rockets, and 
two other PeFfons, undertook the profecuting thefe 
Enquiries ; and having made feveral Experiments as 
well with regard to the Compofition, as the Length 
which Rockets might be made to bear, in propor- 
tion to their Diameters, and of difrerenc-fiz’d Roc- 
kets, from 1 Inch and a half to 4 Inches Diameter, 
they intended this Winter to have made Trial of 
fome of a yet greater Diameter, had not the Death 
of Mr. Da Cofta prevented ir. 
I fhall therefore beg Leave to give fome Account 
of the Succefs which has hitherto attended their 
Undertaking, fo far as they went : And as it has 
been much beyond what was expe&ed, I am in 
hopes this fhort Relation will not prove unac- 
ceptable. 
Amongd fome Rockets fired in the laft Spring, 
there were two made by Mr. EiaCofta of about 3 
Inches and a half Diameter, which were obferved 
to rife, the one to about 833, the other to 91 f 
Yards. At a fecond Trial, made fome time after, 
E e e e 2 there 
