56 SPONTANEOUS COMBUSTION IN COAL CARGOES. 



may require yqvj heavy pruning on one kind of soil naturally rich or highly 

 manured, may require but little on other soil not so rich or in such good 

 condition. There is no better season for pruning the grape than the pres- 

 ent month, and as pruned it is well to lay the canes on the ground and 

 allow them to remain there until ispring. For a trellis or arbor, or side of 

 buildings, it is well to allow about two or three leaders to grow, and this 

 month cut back one-third to one-half of «fjast season's growth, if it is desir- 

 able to confine their growth within certain limits, but if there is a large 

 space to cover, do not cut back. Cut the side granches that grow out from 

 these leaders back to within a foot of the leader, unless the leader is very 

 strong, and the side branches also, and in that case it may be cut back at 

 half the length to reach the next leader. There can not be a better rule 

 applied to all vines than to trim out any part of the vine that is bra^oching 

 out too freely, and train canes where the space is not sufficiently covered. 

 A little practice is the best school, and common sense the best teacher. , If 

 there be trees near by, allow a cane to run into such. Every two or three 

 years allow two or three canes to grow from near the base of vines, and 

 cut out all the old canes, and, having trained all these new canes half way 

 between them, or allowed them to run along near the ground, they can take 

 the place of the old canes as they are cut out. Yines that were set a year 

 ago last spring, and have made a good growth of two or three canes, with 

 small side branches, should have these branches cut back with two or three 

 eyes of the main cane, and the next year allow to grow from these stub side 

 branches wherever needed to fill up vacancies." — Fruit Becorder. 



SCIENTIFIC MISCELLANY. 



SPONTANEOUS COMBUSTION IN COAL CARGOES. 



Some years since a royal commission was appointed in Great Britain to 

 inquire into the causes of spontaneous combustion of coal in ships, and into 

 the remedies possible to adopt for providing against such occurrences. 



The first efforts of the commission were directed to the collection of 

 iaformation bearing on the general condition of the export coal trade, the 

 methods of shipment employed in different parts of the country, the means 

 of ventilation adopted and the particulars of the casualties that had oc- 

 curred so far as obtainable. 



The results of this inquiry showed an export coal trade increasing from 

 42,000,000 tons in 1873 to 14,000,000 in 1875 ; that by far the greatest pro- 

 portion of casualties occur on long voyages, and that they are most frequent 

 in cases where the largest quantities are shipped in one bulk. The propor- 

 tion of casualties to quantity varied from one-quarter per cent, of cargoes 

 under 500 tons to nine i)er cent, in cargoes of over 2,000 tons, and of cargoes 

 destined for California nine casualties occurred out of fifty-four shipments 

 of 500 tons, while out of five ships with cargoes of over 2,000 tons, two 

 were destroyed. 



It was also shown, conclusively, that ventilation, instead of being a pro- 



