Letter from Arthur Storer to Humphrey Babington, dated 1 October 1678
For the Reverend Doct
Babington of Trinity
Colidge in Cambridge
diliver
{2}
Sir Returning you many thancks for your kindness I have Receved an Answer in part from Mr Newton wch is that he had|t|h tryed my Numbers & found them hold well: wch hath Incoradged me once moore to present him with with another Burd, of the same fether hatched at ye said Time & I thinck as well Trimed & dect with fethers yett not Alltogether of so swifft a wing butt Fuly as many chaingeble Noates: I have Likewise a Great many moore such Like Tables wch moast of them ar by duble wayes of working wch I had Allmost filled a Book with wch: wch I thought once yt it would have {comed} to Mr Newtons {wringh} & so thought affter His Examining to have brought it to perfection But now being other wayes Called of I am forced to Lett it Sleepe in Silence: Only I would desire him once moore to Looke over this Table yt hee \may/ see whether the proportions hold good {yea} or no: as I suppose they may or Else I have spent some time therin in vane: {illeg} I suppoase I shall not Receve an answer of wch while I {illeg}|b|e in London for about Saterday or Munday next at the furthest I thinck that I shall take shipp & so fall doune to Graves End wch perhapes if an answer Come soone I may Receive it there otherwayes it may be by affter ships: Haveing no moore at prsent but my service to Mr Newton & my Duty to your selfe with my prayer to God for your Long Life & Comffortabe dayes I Rest your Obedient Nephew
at your Command to Serve you / Arthur Storer
London Octobr ye 1th {sic} 1678:
<4:2r>
The use of this Table to finde the Sun or Stars Altitude uppon Every 5th Azimuth: for ye Latitude of Against the Lat' under the Degrees of Every 5th Azimuth to : you will finde two sumes the first or uppormost sums Sheweth the degrees & min of the the {sic} Equinoctiall Altitude uppon that Azimuth the Next sums under which Being multiplyed with the :S'ine: of the declination: cutt of foore figuers to the Right hand from ye product: then the degree & minute of the sine of the Remainer Being Added to ye degree & min of the Equinoctiall Altitude sheweth the degree & min of ye Altitude uppon that Azimuth for North declination: But if you Substract it from the Equinoctiall Altitude the degree & Min of the Remaner will shew ye Altitude for yt Azimuth for South Declinatio{.} Example Lat' 53: the declination Eather North or South: I demaund the Sunn or Stars Altitude or depression uppon the 60: Azimuth Eather Northwards or Southwards from the East or west: I finde the summ for ye Azimuth under the 60: Azimuth Against of ye Lat' to bee :10486: wch sum I Multiply by the Sine of wch is Rest Nearest 4184: whole sine is which being Added to ye Equinoctiall wch is wch sheweth the Altituded uppon the 60th Azimuth Southwards of the East or west for north declination{.} But for South declination the depression uppon the 60th Azimuth Northwards of ye East or West will be {.}
But if I Add Substract my said sum wch is Being the Suns Altitude uppon ye 60: Azimuth Southwards of the East or West for South declination: wch is his depression uppon yt Azimuth for North declination Northwards &c, I Demaund the Altitude of Hercus & Lyra uppon the Afforesaid 60th &|A|zimuth & Lat' Rest 7496: the sum theareof is — wch is Hircus {\is/ {sic}} Altitude uppon ye 60 Azim South\wards/{.} But if I Substract thus Being the Altitude of Hircus uppon ye 60th Azimuth North Wards
I demaund the Altitude of Lyra uppon the said 60th Azimuth the sum is 10486 wch Summ I multiply by the sine of Lyras declination wch is — Rest 6527 ye Altitude Being uppon yt Azim Southwards of ye East or West: But if you substract for ye Altitude Northwards of ye East or West {so} upon yt Az{.} The Like is to be Observed for ye Sunn or any Other Star for Every 5th or 10th Azimuth Or by proportion to any degree of the Azimuth Or any point of ye Compass If yt you make proportion of boath summs: vizd yt Sum of the Azimuth &: Likewise the degrees & minutes of the Equinoctiall Altitude &c{.}
The Next is the Altitude of ye Sunn or Starr uppon any |5th| Azimuth to finde the declination{.}
<4:2v>For the Resolveing of this Question wch is of Excelent use for the findeing of the Suns place in ye Ecliptick Or his Longitude or the day of the Month Or the declination of any fixed star or the Lat' or declination of any plannet &c this Question being one of the three principall termes whearby is Resolved Moast of the Moast usuall problemes in Astronimy therefore I have at the bottom of the Aforesaid table under Every 5th or 10th Azimuth to of Azimuth Given the proportionable summs whearby is found the Sunn or Stars declination{.} Example Lat' 53: I find the suns Altitude uppon ye 60th Azimu\th/ to be Being southwards of the East or west I demand the declination wch I finde the sine theareof to be 4184 wch sum I sett doune then I Looke at ye bottome of the table under ye 60th Azimuth aganst ye Latitude I finde the sum 9536 wch sum I Multiply by 4184: wch multiplyed by 9536: facit 3989/8624: Rest Nearest 3990: wch is the sine of the Declination desired{.} Againe the Altitude of Hircus uppon the Afforesaid \60th/ Azimuth being Southwards form {sic} ye East or west I demand the declination: the Equinoctiall Azimuth uppon yt \60th/ Azimuth is wch I substract from Rest the Sine thereof is wch being Multiplyed with the Sum of ye Azimuth wch is 9536: facit 7149/1392: Rest 7149: wch is the Sine of the declination desired:
To Calculate the Afforesaid Tables for the finding the Sun or Stars Altitude uppon any Azimuth: Or there Altitude uppon any Azimuth to find the declination{.} First for ye Equinoctiall Altitude uppon any Azim\uth/ Multiply the Tangent of the Complement of the Latitude Given By the sine of ye Azimuth Given cutt of foare figuers to ye Right hand: then the Tangent of ye Remainer sheweth ye Altitude uppon yt Azimuth{.} Thus haveing found the Equinoctiall Altitude uppon the Azimuth Given: The Next is to finde the Second found Sum wch Summs ar sett at the bottome of the Table for ye most Redyest g way of finding the Declination when the Altitude & Azimuth is Given: Which is thus found: Multiply the Secant of the Equinoctiall Altitude of yt Azimuth Given by the sine of the Lat' Cutt of foare figuers to the Right hand from the product Then the Remainer is the Second found Summ: Example ye Equinoctiall Altitude uppon the 60th Azimuth in ye Lat' 53 is the Secant thereof is — 11942: Which summ I Multiply by ye Sine of : wch is : Facit: Rest 9536: wch is the Sum desired: Now the Altitude of the Sunn or any of the Said Stars might as well be found uppon ye said 60 Azimuth as well by this Sum 9536: as well as by the Said Summ shewed befoare wch weare 10486: Onley this perfomes {sic} the work by Multiplication but ye Sum 9536 performes it by Division{.} Example ye declint ye Sine I multiply p 10000 wch sheweth ye Sine of as beffore wch Add & Substracted as before the worke is the same as shewed befoare for ye Suns declinat. But if yt you would have the said sum 10486: & so performe the worke by Multiplication as shewed by the former Exampls Multiply the Radius by ye Radius wch is heare 10000
thus have I shewed 2 wayes for ye finding of ye Altitude of the Sunn or any Star upon Any Azimuth & yt by a duble way of working so yt the product of one Multiplication as shewed beffore will shew the A{illeg}|lt|itude uppon the Azimuth Lett it be Eather South East or South West Nor East or Norwest the declination being Eather North or Sou\th/ /&c\