188 



WRITINGS OF JOSEPH HENRY. 



[1855- 



plied not only to Belgium but also to the whole of Europe, 

 due regard being had to the differences of latitude and ele- 

 vation between Brussels and other places. The correction 

 for each degree of latitude is four days for each degree, to be 

 added or subtracted accordingly as the place is to the north or 

 south of Brussels. The correction for elevation is a retard- 

 ation also of four days for every 330 feet above Brussels, 

 which is itself about 195 feet above the level of the sea. It 

 must be understood that these corrections are only approx- 

 imate, for we are obliged to abstract the consideration of the 

 nature of the soil, the exposure of the plant, and the more 

 or less continental locality, that is the greater or less dis- 

 tance from the sea. 



Plants that grow in Europe and in the United States, whether indigenous or 

 introduced — experiment continued ten years ; by M. Quetelet, of Brussels. 



NAMES OF PLANTS. {Time of leafing.)* 



Acer pseudo-platanus, a maple 



.^sculus hippocastanum, horse chestnut. 



Atnygdalus Persica, peach 



Berberis vulgaris, barberry 



Bctula alba, white birch 



Bignonia catalpa, catalpa tree 



Cratasgus oxyacantha, English hawthorn- 

 Clematis viticella, Italian clematis 



Daphne mezereum 



Praxinus nigra, black ash 



Gleditschia ferox, honey-locust tree 



Juglans nigra, black walnut 



Lonicera Tartarica, Tartarian honeysuckle 

 Magnolia grandiflora, gr. flower magnolia 



Morus alba, white mulberry 



Philadelphus coronarus, mock orange __. 



Populus alba, white poplar 



Populus balsamifera, balm of Gilead 



Prunus cerasus, cherry laurel 



Prunus domestica, common plum 



Prunus spinosa, sloe, black thorn 



Pyrus communis, common pear 



Pyrus malus, apple 



Khus typhina, staghorn, sumach 



Kibes grossularia, gooseberry 



Kibes rubrum, red currant 



Kibes nigrum, black currant 



Kobinia pseudo-acacia, white locust 



Sorbus aucuparia, mountain ash 



Tilia Europsea, European linden tree 



Latest. 



April 



April 



April 



April 



April 



May 



April 



April 



April 



May 



May 



May 



April 



April 



May 



April 



May 



April 



April 



April 



April 



April 



April 



May 



April 



April 



April 



May 



April 



April 



28 



27 



19 



14 



20 



19 



16 



20 



4 



5 



26 



10 



5 



29 



15 



13 



1 



22 



21 



23 



23 



22 



20 



7 



3 



10 

 21 

 22 



* Latitude of Brussels. 



