Published in 1878. First edition thus. Some staining and age toning to page extremities with small spots of foxing through out. Text block is solid. Some math calculations in pencil to the top edge of p. 5. Two handwritten charts in fountain pen, "Correction for reducing readings of Barometer to Sea Level, Sable Island - N.S." and "Index Corrections for Thermometer No. C 3484" pasted down to the verso of the front board. Pencil drawing to the rear end paper opposite which are four neatly pasted in photo's of a "modern" thermal shed. It would appear the very last page has been torn out. Gilt titles to front board with blind stamped ruling and devices. Boards are rubbed and worn, especially to extremities. They have been professionally re-attached and repaired. 4.5 cm loss to the head of the spine and 1cm loss to the foot of the spine. Part of the title to the spine, in gilt, has survived, ".ructions to Observers. 1878". A scarce title in any condition.