ESTIMATION OF THE HEAT NECESSARY TO GROWTH. 



559 



add together the daily maxima of sun-temperatures fi-om the first of January 

 until the event in question takes place. 



A selection of constants obtained in this way from observations extending over 

 many years in Central Germany (Giessen) may be suitably inserted here. 



Constants for the Issue of the Foliage-leaves from the Buds. 



Gooseberry {Ribes Orossularia) 478°, 

 Hazel {Cori/lui Avellana) 1061°. 

 Beech {Fugus silvatica) 1439°. 



Plane {Platanus acerifolia) 1503°. 

 Walnut (Juglans regia) 1584°. 



Constants for the Opening of the First Flowers. 



Hazel {Corylus Avellana) 226°. 



Mezereon {Daphne Mezeream) 303°. 



Snowdrop (Galanthus nivalis) 311°. 



Sweet Violet ( Viola odorata) 576°. 



Cornel (Coriius mas) 576°. 



Apricot {Pruniis Armemaca) 843°. 



C'orydalis {Corydalis cava) 863°. 



Violet Willow {Salix Daphnoides) 968°. 



Cowslip {Primula veris) 968°. 



Norway Maple {Acer platanoides) 1100°. 



Peach {Persica vulgaris) 1100°. 



Gooseberry {Ribes Orossularia) 1138°. 



Almond {ximygdalus communis) 1196°. 



Gean {Prunus avium) 1265°. 



Sloe {Prunus spinosa) 1265°. 



Pear {Pirus communis) 1304°. 



Bird Cherry {Prunus Padus) 1325°. 



Apple {Pirus Malus) 1423°. 



Plum {Prunus domestica) 1423°. 



Alpine Woodbine {Lonicera alpigena) 1458°. 



Oak {Quercu-s pedunculata) 1556°. 



Lilac {Syringa vulgaris) 1556°. 



Walnut {Juglans regia) 1584°. 



BarbeiTy {Berberis vidgaris) 1615°. 



Poet's Narcissus {Narcissus poeticus) 1615°. 



Hawtliorn {Crataigus Oxyaeantha) 1649°. 



Lily of the Valley {Convallaria inajalis) 1649°. 



Horse Ch^sinwi {JE sculus Hippocastanum) 1708°. 



Peony {Pwonia officinalis) 1818°. 



Laburnum {C'ytistcs Laburmim) 1818°. 



Mountain Ash {Sorbus aucuparia) 1844°. 



Norway Spruce {Abies excelsa) 1904°. 



Plane {Platanus acerifolia) 2115°. 



Elder {Sambucus nigra) 2313°. 



Deadly Nightshade {Atropa Belladonna) 2346°. 



Acacia {Robinia Pseudacaeia) 2404°. 



Scotch Pine {Pinus sylvestris) 2404°. 



White Water Lily {NympluBa alba) 2506°. 



Arnica montana 2538°. 



Tulip Tree {Liriodendron tulipifera) 2538°. 



Rosa centifolia 2538°. 



Fox-glove {Digitalis purpurea) 2640°. 



Carthusian Pink(Z'ictnZÄJtj Cart/tusianoru7n)2G40°. 



Vine ( Vitis vinifera) 2878°. 



Broad-leaved Lime {Tilia grandifoUa) 3033°. 



Small-leaved Lime {Tilia par vifolia) 3274°. 



Oat {Arena saliva) 3444°. 



White Lily {Lilium candidum) 3378°. 



Chestnut {Castanea sativd) 3660°. 



Immortelle {Helichrysum arenarium) 3918°. 



Ling {Calluna vidgaris) 4164°. 



Trumpet-tree {Calalpa syringcefolia) 4275°. 



Blue Aster {Aster Amellus) 4874°. 



Syi-ian Marsh-Mallow {Hibiscus Syriacus) 4986°. 



Meadow Salfron {Colchicum autumnale) 5024°. 



Ivy {Hedera Helix) 5910°. 



Constants for the Eipening of Fruit. 



Wild Strawberry {Fragaria vesca) 2671°. 

 Gean {Prunus avium) 2778°. 

 Mezereon {Daphne Mezereum) 2935°. 

 Red Currant {Ribes ridirum) 3069°. 

 Gooseberry {Ribes Orossularia) 3596°. 

 Alpine Woodbine {Lonicera alpigena) 4164°. 

 Mountain Ash {Sorbus aucuparia) 4339°. 

 Barley {Hordeum vulgare) 4403°. 

 Apricot {Prunus Armeniaca) 4435°. 

 Apple {Pints Malus) 4730°. 



Barberry {Berberis vulgaris) 4765°. 



Carthusian Pink {Dia nth us Carth usianorum)^&li°. 



Elder {Sambucus nigra) 4913°. 



Pear {Pirus communis) 5024°. 



Cornel {Cornus mas) 5416°. 



Plum {Prunus domestica) 5780°. 



Vine ( Vitis vinifera) 5780°. 



Peach {Persica vidgaris) 6004°. 



Horse Chestnut {Alsadus Hippooastanum) 6034°. 



Oak {Quereus pedunculaia) 6236°. 



