18 



NEW ENGLAND FARMER. 



posts al the distance of one or two feet from the wall, 

 it would be much better for common edifices, but it is 

 more particularly advisable for powdcr-magaxims, 

 powder-mills, and all such buildings as contain com- 

 bustibles ready to take firn. The upper end of the 

 conductor should be terminated in a pyramidal form, 

 with the edges, as well as the points very sharp ; and il 

 the conductor be of iron, it should be gilt or painted for 

 the length of -rue or two feet. This sharp end should 

 be elevated above the highest part of the building, (as 

 above a stack of chimnies, to which it may be fasten- 

 ed) at least five or six feet. The lower end of the 

 conductor should be driven five or six feet into the 

 ground, and in a direction leading from the founda- 

 tions ; or it would be better to connect it with the 

 nearest piece of water, if any at hand. If this con- 

 ductor, on account of the difficulty of adapting it to 

 the form of (he building, cannot conveniently be made 

 of one rod, then care should he taken, that where the 

 pieces meet they be made to come in as perfect con- 

 tact with one another as possible ; for the electricity 

 finds considerable obstruction where the conductor is 

 interrupted. 



For an edifice of a moderate size, one condu:tor, in 

 the manner already clescribed, is perhaps si-ificient ; 

 but in order to secure a large building from sustaining 

 any damage by lightning, there should be two, three, 

 or more conductors, in proportion to the extent o( the 

 building. 



" In ships a chain has often been used for the purpose, 

 ■which, on account of its pliableuess, has been found 

 very convenient, and easy to be managed amcng the 

 ringing of the vessel ; but as the electricity finds a 

 great obstruction in going through the several links, for 

 which reason chains have actually been broken by the 

 lio-htning, so their use has now been almost tntirely 

 laid aside ; and in their stead copper wires a little 

 thicker than a goose quill have been substituted, and 

 have been found to answM- very well. One of those 



„. .^.ouiu oe elevated two or rnree feet above the 



highest mast in the vessel ; this should be continued 

 down the mast as far as the deck ; where, by bendiug, 

 it should be adapted to the surface of those parts, over 

 •which it may most conveniently be placed, and, by con- 

 tinuing it down the side of the vessel, it should always 

 be made to communicate with the water of the sea. 



Rees' Cyclopedia says, " a communicaticn should 

 be made between the conductor, and all other pretty 

 large pieces of metal in the building, such as leaden 

 spouts, large iron clamps, &c. ; for otherwise a lateral 

 explosion may take place between those detached 

 pieces of metal, at the time that the lightning is con- 

 veyed by the conductor, and thence the building may 

 receive some damage, though not in a very great de- 

 gree, unless indeed in the case of powder-mills, and 

 powder-magazines." 



A writer whose communication on this subject was 

 republished from the Boston Recorder, in the N. Eng- 

 land Farmer, Vol. 11. page 77, says : 



"The greatest deficiency I have noticed [in the 

 construction of lightning rods] is in the want of a free 

 communication with moist earth. When a rod is in 

 all other respects perfect, and deficient in thL«, so far 

 from being a safeguard, it only increases the danger it 

 was intended to avert. 



" I have known, and by good authority have heanl 

 of several buildings, having conductors, but which 

 •lid hardly touch the earth, being damaged by light- 

 ning. Among the many is the meeting house in Rf ad 

 ing, Mass. In the course of the present summer th^ 

 hgbtniog came down the rod, and went ofi" near the 



miii'i:' to px'errnitvttp thnm. — Four yours since 

 1 hu 1 1 (eivof Ihnse fast sprraiiiiitr thistlns in 



bottom into, and damaged the hoiire. This was rm 



doubtedly, because, by reason of ti.e rod not goinf 



into the ground, the electrical fluid could not pass off two [.lare^ in mv pastur.; : they were then con 



asfistas it was received, and the rod became over- jfin^.l to a lew Ip.t in c.rcumference H:>vino 



wllnessci! the 



peri 



elect 



conductor. 



" I shall, therefore, endeavor to give some directions 

 for the information of those who are unacquainted with 

 the subject, and who have not the means of informa- 

 tion. 



"The rod should be made of round, smooth iron, at 

 least three qiarters of ou inch in diameter, and when it 

 can conveniently be done, instead oflioki.ig, sho.dd h. 

 smoothly welded together ; but when by reason of Hi 

 length or otherwise it is inconvenifnt to weld tLc 

 whole rod, let it be smiDthly connected, by screwing 

 the end of one part into the end of another. Th. re 

 should be five or more points, one in the centre, per- 

 pendicular, and the others oblique. They should be 

 filed to a sharp, slender point, and tipped with silver. 

 The points should be elevated at least five or six feet 

 above the highest part of the building. The bottom of 

 the rod should go into the earth six or seven feet, and 

 terminate in a bed of two or three bushels of wet char- 

 coal. The wet coal covered with earth will probably 

 retain dampness longer than any other substance. 



" A conductor constructed and put up agreeably to 

 the above directions, will perfectly secure a building 

 for twenty feet on every side. When a building is 

 more than forty feet long, for perfect security, th»re 

 should be two or more rods, calculating one rod for 

 every forty feet." 



These directions appear to us to be correct and judi- 

 cious. The conductor may be considered as the channel 

 which conveys the electric fluid from the cloud to the 

 earth in most cases, tho' we are told that this fluid some- 

 times ascends from the earth to the clouds. In either 

 case, the larger the rod or channel of electricity, and 

 the fewer the obstructions in its course the more per- 

 fectly it answers its purpose of drawing ofi' the excess 

 ot the fluid without a stroke or explosion. Some wri- 

 ters recommend tipping the points of lightning rods 

 with platina or gilding them. Probably tipping them 

 with silver will answer as good a purpose, as the prin- 

 cipal object is to prevent rust, which in a great mea- 

 sure destroys the conducting power of the metal. We 

 believe that there is not much danger of the lightning^ 

 leaving the conductor, and following the iron staples. 

 But it will be somewhat more safe and probably as 

 convenient " to pass the rod through a small ledge 

 of wood, which is nailed fast to the building," or to 

 " make use of a small iron staple with a piece of horn 

 inserted into the ring, which receives the rod," as our 

 correspondent says, is the practice of some of his neigh- 

 bours. Though horn is not enumerated by writers, 

 (SO far as we have examined) among the electrics, or 

 non-conductors of electricity, yet we know it to be a 

 Very slow conductor of heat, and imperfept conductors 

 of heat are generally slow conductors or non-conduc- 

 tors of the electric fluid. 



CANADA THISTLE. 

 To the Editor of the Massachusetts Spy, 



Sir, — I ohserved a petition was presented to 

 (he Legislature reqiipsling their aid (o prevent 

 llio spread of the " Canada Thistle ;" and 1 



will: full expectation, that they would IrouVde 

 ine no more. The next year, there were more 

 than twice the number, and occupied a inucli 

 larger piece of ground. 1 (hen cut (hern wnh a 

 scvfhe, as often as they grew srifficiciitly high to 

 |)P cut — al! this, apparently, served to increase 

 their growth. The next ye.ir, they exiended 

 several rn Is, and 1 had every reason to believe, 

 that in a few years. Ihey would willingly occu- 

 py iny whole pasture. Knowing that salt, or 

 brine would destroy many kinds of vegetables, 

 I cut them with a scythe at the commencement 

 of a rain, and ihr-w salt liberally over them, 

 mi my cattle and sheep kep! the grass and this- 

 tles closely fed in conseipience of the salt. I 

 salted the ground a second time the same year, 

 and they are entirely ilestroyed. — If those peo- 

 ple, who find Canaila Thistles in their lots, or 

 bv "■ the way side" will take the trouble to maka- 

 tliiis simple appticalion, they may perhaps pie- 

 vent the growth of the thistle, and supersede 

 the necessity of a legislative act. 



A FARMER. 



GAPES IN CHICKENS, 

 Occasioned by double headed worms, which ac- 

 company this communication, together isith a 

 biazen wire screw, with which they are easily 

 extracted. 



Synapuxent, IGih June, 1824. 



TO THE EDITOR OF THE AMERICAN FAAMER. 



Dear Sir. — The enclosed papers will apprise 

 yon that your inquiry, when I last had the plea- 

 sure of seeing yon, was not correctly under- 

 stood. I shall be pleased to hear from you 

 when additional light shall have been thrown 

 upon the subject to which they relate. 



Willing at all times to minister to that laud- 

 able thirst for information which characterises 

 you, 1 herewith forward a double headed por- 

 tion of the vermicular family, together with 

 the instrument with which they were taken 

 from the wind pipes of four chickens in great 

 distress with the ga/)cs. The ingenious neigh- 

 bour who invented the instrument, ivas kind 

 enough, after he had operated upon our chick- 

 ens, to give it to me, exactly as ! now enclose 

 it for your inspection. I declare to you that I 

 have seldom been more surprised, than at the 

 facility with which this brazen screw was in- 

 troduced into the wind pipe — the struggles of 

 the subject ceasing as soon as its point had fiiir- 

 ly passed the chink, (rima glottidis if you pre- 

 fer it,) the almost undisturbed respiration, 

 whilst it was suffereil to remain projecting from 

 the mouth for a minute. Without other support 

 than that which the wnlls of the tube itself af- 

 forded — and the astonishing organization of the 

 worms taken out. You will perceive at first 

 view that many of these monsters have two 

 fimbriated, and all a pointed extremity. The 

 gentleman who extracteil Ihemassureil me that 

 ose which appear without the small head 



have heard many enquiring the most successful j must have been mutilated, as be bad seeanoae 



