AvRiL I, i886,j THE TKOPICAL AQklCULfiJkl$fi 



ni 



have beea to accumulate aud collate the mass of 

 oviileuco which must be available from the experieuce 

 <if planters aud agents themselves. It is onlj^ by a 

 loniparisou of such experience that a true solution 

 of this vexed (juestion can be safely arrived at. 



In 1883 Dr. 'Wigner published a Paper on the 

 packing of substances of delicate odour, such as Tea, 

 and he refers therein to experiments which he had 

 made during the previous five years regarding the 

 alleged effect of certain Indian woods on tea-lead. 

 He came to the distinct conclusion that the corrosion 

 of the tea-lead was due to the generation of acetic 

 or other volatile acid, which, in the presence of 

 carbonic acid and moist air, would account for the 

 corrosion complained of. Mr. I'edler is iu agreement 

 with this opinion, and he says that- in almost all 

 respects the experiments he has himself made con- 

 firm the theory put forth. To test the matter 

 efficiently, certain boxes of tea were specially prepared, 

 and the wood, the hning, and the contents, subjected 

 to separate tests. 



The first experiment made was on a box madr of 

 damp uusoasoned wild mango-wood. After being kept 

 for several weeks unopened, it was found that the 

 6urfacr3 of the lead ikH the wood was almost entirely 

 covered with a white powder, principally " wliite 

 lead." In some places the lining was entirely eaten 

 through, aud all over the whole external surface 

 corrosion had set in, but the side of the lead next 

 the tea was found bright and free from corrosion, 

 although slightly tarnished,— the latter probably due 

 to imperfect drying, and consequent insufhcient chock 

 of fermentation. Fuither, the surface of the wood 

 next to the lead wa.s found to be distinctly acid to 

 test-paper. 



A second experiment was made by distilling some 

 of the wood of the box in a current of steam, and 

 the distillate was then tested by placing it at the 

 bottom of a bottle. A piece of tea-lead was then 

 hung iu the bottle so that it did not touch the 

 liquid, aud the bottle was repeatedly tilled with air 

 charged with moist carbonic acid; with the result 

 that distinct corrosion took place. Various other 

 experiments were made, and care taken to use 

 scaiunS'i wood as well as wood damp, or partly seasoned 

 only. The result was the same, although the effect 

 was more rapid in the ease of unseasoned wood. 

 Boxes made of other kinds of wood were then ex- 

 perimented with, aud in five out of six cases no 

 corrosion took place, aud there was no perforation. 

 The conclusion arrived at by Mr. Pedler is, that the 

 experiments prove that the active agent in the 

 corrosion of the lead linings in the exam|iles taken 

 was not produced from the tea contained in the 

 chests, but from the wood of which they were fornaul. 

 M'e have not space to follow seriatim the m.my 

 and virions experimi^nts made, but the result arrived 

 at has been to prove — L That unseasoned mango- 

 wood attacks lead, iu a moist atmosphere, violently. 

 -. That seasoned mango-wood kept dry has no action 

 on it. 3. That seasoned mango-wooil subseiiuentlv 

 saturated with water becomes again in a condition to 

 attack lead in the presence of a moist atmo.iphere, 

 although not so violently as un.seasoned wooil. 4. That 

 nnseasoned and damp wood of an;/ litsciiptinn corrodes 

 the lead more or less. 5. That the corroding sub- 

 stance, whatever it be, must be formed gr.adually in 

 the wood, and that the formation is connected with 

 the continued pre.sence of moisture. 



The latter conclusion should be taken to heart by 

 those who, unthinkingly, use woods, of whatever 

 kind in anything like a green state. In the Terai 

 wa have seen boxes made from almost green wood, 

 and we well recollect remarking that they would 

 split to pieces in anything like a rough journey; 

 but it did not occur to us, then, that far more 

 serious consequences might follow, in the corrosiiin 

 of the lead itself. Now that this has, however, been 

 conclusively proved, it is to be hoped that the use of 

 unseasoned wood may bo rigidly interfered with, for, 

 given hejt and moisture to set up putrefactive 

 fermoatation therein, the presence of all the sub- 



stances necessary to corro Ic tea-lead will, says Mr. 

 Pedler, at once follow; and few, we think, will be 

 inclined to di.spute such self-apparent logic, although, 

 hitherto we have not snflicieutly regarded the fact. 

 Most men, even though knowing little of chemistry, 

 would incline to the belief that tea, properly manu- 

 factured, could hardly have any chemical action on 

 its lead covering, any more than that lead free from 

 contact with decomposing influences could effect the 

 tea, but it is satisfactory to have the matter author- 

 itatively set at rest; and we now know for certain 

 as the results of mucli painstaking scientific observation 

 by an eminent exi)ert, that if damp and unseasoned, 

 wood is used for the manufacture of Tea boxe.s, 

 corrosion of the lead is, under favorable circumstances, 

 almiisi certain, although some varieties of wood may 

 act more violently and rapidly than others. We learn, 

 also, that even seasoned wood allowed to become 

 saturated, m.ay produce, under circumstances of high 

 teriiperature, putrefaction, or corrosion of the lead 

 lining. The necessity, therefore, for protecting chests 

 from moisture, in transit, is impressed upon us; for 

 it has been further demonstrated that Tea can easily 

 take up the disagreeable odour which damp wood 

 may emit. 



It is most satisfactory to find that this much-ve.xed 

 question of the deterioration of Toa from the use 

 of unsuitable woods for packing, or from the use 

 even of suitable n-ooila unseasoned, has been author- 

 itatively disposed of.— IiuHaii Tea Gazette. 

 -•■ - - 

 THE CULTIVATION OF 00(^A.» 

 liv itKKRY If. nrsiiv, M.D. 

 For more than two months the writer has been 

 continuously engaged in the study of the coca-plant 

 and its products iu the districts of Bolivia which pro- 

 duce the best i|uality of leaves. The results, which are 

 likely to greatly increase the recently-created interest 

 in the plant, will be published .shortly, when his 

 studies .shall have been conclnded. At the present 

 i time I will ouly discuss a (]uestion concerning which 

 speculation is rife, namely, the adaptability of the 

 plant to culture in countries where it is now un- 

 known. 



For the details concernhig cultivation here presented 

 I am chiefly indebted to Jlr. Oscar Lohsc, one of the 

 most intelligent cultivators in this country, and pro- 

 prietor of the I'inca of San Antonio, two leagues from 

 the town of Oaroica, Yungas. 



The district of Oaroica may be considereil as fitly 

 repre.senting the remainder of Yungas, and Yungas as 

 representiijg the princip.il coca districts of this republic. 

 The conditions of soil and clintate may be briefly 

 stated. Proceeding eastward from La Pa/., itsrif .sonie- 

 wliat more than ten thousand feet f above the sea, 

 for a ilistaucu of four or five leagues, we reach the 

 summit of the pass over the easterumost coidillera of 

 the Ande.s, this cordillera having an average elevation 

 in this immediate district of perhaps sixteen thou.'iaiid 

 feet. This ridge, always more or less snow-cnvere'l, 

 cuts off a large portion of the westward-bound cluuls, 

 which are thus either precipitated in the form of rain 

 before reaching the summit, or. arriving there, are 

 deposited in the form of snow, and then returned bv 

 means of rivulets to the valleys, chiefly of the eastern 

 slope. It should be noted that in Northern Peru and 

 Ecuador this cordillera is higher than here, so that 

 the eastern slope in those regions is more profusely 

 and regularly watered than here. From this pass, hail 

 we a direct roail, we could travel iu half a d.iy, so 

 steep is the descent, to the banks of the Oaroica Iliver, 

 having an altitude of only two thousand four huudred 

 feet. >\'heu we have descended to six thousand four 

 hundred feet we should meet with our first coca 

 plantatious, and after pas.sing two thousand feet level 

 we shou ld have left them principally or entirely be- 

 * From the Thtvapoitic Gazettn^ -Tanuary. 

 t I have given altitudes and measurements ap- 

 proximately in English feet. By the Spanish niea- 

 •uretnents the altitudes are much greater. 



