43 
It had, however, become evident that the heating Voir had 
reached a state which was extremely pr recarious. Her Majesty's Office 
of Works therefore included, in the estimates for 1894-5, a sum of 
1,0004. for its partial renewal. . During the summer of that year this was 
vitat iotory accomplished for the north wing. The. ceiling of the 
furnace room was raised 21 ft., and E the pipes which had hitherto 
either been buried in brickwork or carried under the beds, were 
renewed and re-arranged so as to be immediately accessible. 
These operations involved clearing a large portion of the north wing. 
The opportunity was therefore taken to execute other necessary repairs, 
and to repaint the whole of the interior 
Th ength of Mwst pipes in the Palm House has been 
r about miles. Notwithstanding, it has 
«Nye t den difficult to "iétitufn a vibe temperature in the north 
wing during winter. This was espec ially the case during wind, the 
cold air forcing its way through the * laps" of the glass, which necessarily 
fit imperfectly, owing to the curved surface of the house. To counteract 
this, and avoid the necessity of a the boilers in severe weather, 
an additional 4 in. pipe was earried r Aa entire north balf of the 
house and attached to a new auiem ue 
In 1877 a hot-water pipe was carried round the gallery, * the heat 
checks the drip and downward draughts, which had long proved so 
injurious to the plants." This had proved so satisfactory in working 
that it was determined last year to extend the principle, and a 2} in. 
pipe was, in addition to. the lower auxiliary pipe, carried round the 
inside of the lantern of the north end. 
he general result of these iraprovements has been to render it 
possible to attain, during the E yrs a OA and sufficient 
tem ee end in : du^ impra ^b .- The hole of the works 
XY. Pitinienddus of the resident 
itani CAE of po Mas Mr. J. "lén 
Green-glass in Plant-houses. —It is well known that the use of glass 
of a green tint has for half a century been a characteristic peculiari rity 
of the plant-houses at Kew 
It was adopted as the result of re reports rts made to the Office of Woods 
in 1845-6 by the late apaes Robert Hunt, F.R.S. These reports are to 
bè found i in the appendix to his “ Researches on A ác: el ed. “re ee 
“states (p. tie —* [t is required, aecordin 
letter of the 23rd of November, that a maree raa rapa fot the 
pone À— Kew, *so much stained as will died the — of its 
and not affect the vegetation.” Green 
green, ipe but will obstruct the passage of those rays which i. m 
the ‘scorching’ desired to be avoided." He further adds 81): 
*1 have et ai a glass which is so slightly tinted as to 
present no appearance, by either reflected or transmitted light, mate- 
rially different from the white sheet glass eds employed for glazing 
ew. . . . This glass admits most freely the permeation of all 
which at any rate of late years has been used at Kew is certainly ofa 
much darker tint than that prescribed by Mr. Robert Hunt, and is 
