a gs in Hydraulie Mortar. 101 
Medicago lupulina, Z Rumex — Ji 
? maeulata, Sibthonp. ; a, L: 
Rosa rubiginosa, d Cheno ajhai murale, L. 
Lythrum hyssopifolium, L. Amaranthus sores Py L. 
Apium leptophyllum,* F. Muell. rofle ^ie 
Erigeron canadense, L. Euphorbia aiden 
Senecio vulgaris, Z. T = lio oscopia, Z 
Carduus marianus, Gertn. Tris germani 
ut nceolatus, L. Agave ame ricana el 
Hypocheris radicata, L. Phalaris canariensis, E. 
Xanthium spinosum, L. Holcus mollis, 
Anagallis arvensis, L Anthoxanthum odoratum, L: 
Physalis peruviana, Z Panicum sanguinale, Scop. 
I m barbarum, Z Cynodon dactylon, Z. 
Veronica serpyllifolia, Z Agrostis vulgaris, With. 
h aquatica, L Poa annua, L. 
Stachys arvensis, L saat p rata, L. 
iie ite vulgare, L Festuc Wired n Sm. 
1 i, L. L dbi ho renn 
Plantagy major, L. 
Arr. XL—0On some Experiments in Hydraulic Mortar, in Auckland. 
By James Stewart, Assoc. Inst. C.E. 
[Read before the Auckland Institute, 6th July, 1868.] 
Tue importance of obtaining, in Auckland, a lime of sufficient hydraulicity 
to enable it to be used in mortar intended for wet situations, has long 
impressed the writer. The absence of such, in regular supply, leads to great 
expense in the employment of cement, which is always, when obtainable, very 
dear, and, so far as has come within the writer’s experience, of not more 
than one-half the value of the best as used in England. 
The lime commonly used in the making of mortar in Auckland, is obtained 
from sea shells, or limestone from Mahurangi. The shell lime is, of course, 
rich lime, and possessing no hydraulicity more than that from pure chalk. 
The stone lime usually worked is not in any appreciable degree hydraulic, 
neither is it so rich as the shell lime. If properly used, however, it is 
preferable to shell lime for all work. In dry situations it sets very hard, 
and takes a good surface by the gradual reversion to the state of carbonate 
of lime. The writer has never seen an analysis of this lime, but he has 
tried, mechanically, several samples of it in the state of hydrate of lime, by 
separating the sand mechanically combined, and has usually found about 
20 per cent. of sand present. | 
Having ascertained that lime had, on several occasions, been obtained at 
Mahurangi and Whangarei, possessing some qualities very differeht from 
FP ob Wis chadeved in tk 1 pica a ibo 
It is found in East Australia and North and en. perendi 
