142 Sir Norman Lockyer and Mr. F. 0. Penrose. Attempt to 



for more than 1 300 feet from the centre of the temple, and particularly 

 the line of the bottom of the ditch from which the earth was taken to 

 form the bank, and which runs parallel to it. Measurements taken 

 from this line assisted materially those taken from the crown of the 

 bank itself. "With this help and by using the southern bank and ditch 

 whenever it admitted of recognition, a fair estimate of the central line 

 could be arrived at. To verify this, two pegs were placed at points 

 140 feet apart along the line near the commencement of the avenue, 

 and four others at distances averaging 100 feet apart nearer the 

 further recognisable extremity, and their directions were measured 

 with the theodolite, independently by two observers, the reference 

 point being Salisbury Spire, of which the exact bearing from the 

 centre of the temple had been kindly supplied by Colonel Johnston, 

 R.E., the Director-General of the Ordnance Survey. The same was 

 also measured locally by observations of the Sun and of Polaris, the 

 mean of which differed by less than 20" from the Ordnance value. 

 The resulting observations gave for the axis of the avenue nearest the 

 commencement an azimuth of 49" 38' 48", and for that of the more 

 distant part 49 32' 54". The mean of these two lines drawn from 

 the central interval of the great trilithon, already referred to, passes 

 between two of the sarsens of the exterior circle, which" have an 

 opening of about 4 feet, within a few inches of their middle point, the 

 deviation being northwards. This may be considered to prove the 

 close coincidence of the original axis of the temple with the direction 

 of the avenue. 



This value of the azimuth, the mean of which is 49 35' 51", is con- 

 firmed by the information, also supplied from the Ordnance Survey, 

 that from the centre of the temple the bearing of the principal bench 

 mark on the ancient fortified hill, about 8 miles distant, a well-known 

 British encampment named Silbury or Sidbury, is 49 34' 18", and 

 that the same line continued through Stonehenge to the south-west 

 strikes another ancient fortification, namely, Grovely Castle, about 

 6 miles distant and at practically the same azimuth, viz., 49 C 35' 51". 

 For the above reasons 49 34' 18" has been adopted for the azimuth of 

 the avenue. 



The present solstitial sunrise was also watched for on five successive 

 mornings, viz., June 21 to 25, and was successfully observed on the 

 latter occasion. As soon as the Sun's limb was sufficiently above the 

 horizon for its bisection to be well measured, it was found to be 8' 40" 

 northwards of the peak of the Friar's Heel, which was used as the 

 xeference point, the altitude of the horizon being 35' 48". The 

 azimuth of this peak from the point of observation had been pre- 

 viously ascertained to be 50 39' 5", giving for that of the Sun when 

 measured, 50 30' 25", and by calculation that of the Sun with the 

 limb 2' above the horizon should be 50 30' 54". This observation 



