057. Primo Levi a Hermann Langbein, 31 ottobre 1983

Torino, 31 ott. 1983[1]

Caro Hermann,

come ti avevo promesso, ti mando di seguito le mie osservazioni sul capitolo «I due gas tossici», p. 281 sgg. del libro che mi hai dato.[2]

1) A p. 282 e 283 si parla di «einen reizerzeugenden (…) Wasserstoff». Credo che sia un errore, perché l’idrogeno (= Wasserstoff) ha proprietà completamente differenti, e quindi si dovrebbe leggere Warnstoff.[3] Infatti, in un libro che avevo letto tempo addietro (D. Meyer, «La guerra dei gas e le armi chimiche», 1926) trovo che il Zyklon B era (o è?) una miscela di acido cianidrico (= Cyanwasserstoff) con ca. il 10% «di composti alogenati come cloro- e bromocarbonato di metile ed etile», la cui funzione è segnalare attraverso l’odore, che è molto intenso e irritante, eventuali fughe del prodotto. A questo proposito, non capisco bene il termine «protegge» (p. 282, penultima riga): sarebbe più adatto qualcosa come «rafforza, intensifica».

2) Il termine «Schwefeläther» (p. 283) è oggigiorno desueto: si dovrebbe sostituire con «Äthyläther».[4] Il ragionamento che segue non è corretto, perché dipende dalla scala termometrica scelta (per esempio, sarebbe 111 gradi anziché 132 se utilizzassimo la temperatura assoluta); meglio non indicare una quantità e limitarsi a dire che la superficie del corpo umano è sempre molto più alta del punto di ebollizione dell’acido cianidrico. A ogni modo non è fondamentale, e i «faurissoniani»[5] sbagliano a battere su questo tasto: la tensione di vapore (Dampfdruck) dell’acido cianidrico è già fortissima a temperatura ambiente. A Monowitz (e senz’altro anche ad Auschwitz I) il Zyklon B si usava per uccidere i pidocchi nei block, persino d’inverno.

3) A p. 285, il passaggio da «Unter diesen Vermittlern…» fino a «mit dem Ausdruck „Cytochromo-oxydase“» non è chiaro e si direbbe che manchi qualcosa: ma non essendo un fisiologo, non oso fare correzioni.

4) In tutto il capitolo le formule chimiche sono scritte secondo l’uso francese e non tedesco (e italiano). Si dovrebbe scrivere HCN anziché CNH, KCN e NaCN anziché CNK e CNNa; in particolare, la reazione di p. 286 (in basso) andrebbe scritta così:

Ca (CN)₂ + 2H₂O > 2HCN + Ca(OH)₂

ovvero con i numerini in basso e la freccia al posto del segno =.

È tutto. Sono certo che comprenderai i motivi della mia pignoleria: è che i nostri avversari sono pignoli, non depongono le armi, e sarebbe preferibile non farsi cogliere alla sprovvista da loro, o persino doverne subire le critiche.

Spero che tu sia contento del Convegno. Non ho molta esperienza in merito, ma ho l’impressione che tu sia stato piuttosto bravo, senza cadere nell’eccesso di retorica né in ripetizioni. A mio avviso la tua relazione e quella della signorina Bravo[6] sono state le migliori.

Mi auguro che il ritorno a Vienna sia andato bene e sono felice di averti rivisto in buona salute e in piena attività come al solito. Ho cercato di ottenere da Mursia qualche notizia sulla traduzione di Uomini ad Auschwitz, ma per adesso senza risultati: ti terrò al corrente. Per intanto, ti stringo cordialmente la mano.

Turin, Oct. 31, 1983[1]

Dear Hermann,

As I promised, I am sending you here my observations on the chapter “Die zwei Giftgase,” p. 281 ff. of the book you gave me.[2]

1) Pp. 282 and 283 discuss “einen reizerzeugenden (…) Wasserstoff.” I think that there is an error, because hydrogen (=Wasserstoff) has completely different properties, and that it should read Warnstoff.[3] In fact, in a book that I read in the past (D. Meyer, Der Gaskampf und die chemische Kampfstoffe, 1926) I find that Zyklon B was (or is?) a mixture of hydrogen cyanide (=Cyanwasserstoff) with approx. 10% “of halogenated products of the methyl- and ethyl- chloro- and bromocarbonates type,” whose function is to indicate by their odor, which is very strong and irritating, possible leaks of the product. Regarding this, I do not quite understand the term “protect” (p. 282, next-to-last line): it should read something like “strengthens, intensifies.”

2) The term “Schwefeläther” (p. 283) has been out of date for a long time: it should be replaced with “Äthyläther.”[4] The reasoning that follows is not correct, because it depends on the thermometric scale that has been chosen (for example, we would find 111 degrees instead of 132 if we used absolute temperature); better to avoid quantification, and simply say that the surface of the human body is always much higher than the boiling point of hydrogen cyanide. In any case, the point is not essential, and the “Faurissonians”[5] are wrong to insist on it: the vapor pressure (Dampfdruck) of hy. cy. is already quite high at ordinary temperatures. At Monowitz (and surely at Au. I also) they used Zyklon B to kill lice in the blocks, even in winter.

3) On p. 285, the passage from   is not clear, and it seems as if something is missing: but, not being a physiologist, I’m wary of making any corrections.

4) In the entire chapter, the chemical formulas are written following French usage, not German (and Italian). It should read HCN instead of CNH, KCN and NaCN instead of CNK and CNNa; in particular, the reaction on p. 286 (bottom) should be written as follows:

Ca (CN)₂ + 2H₂O > 2HCN + Ca(OH)₂

i.e., with the little numbers at the bottom and an arrow instead of the = sign.

That is all. I am sure you will understand the reason for my meticulousness: it is because our adversaries are meticulous and do not give up the fight, and when facing them it would not be pleasant to be taken by surprise, or even to have to endure their criticism.

I hope you are satisfied with the Conference. I do not have a great deal of experience with conferences, but my impression is that everything went quite well, without too much rhetoric or too many repetitions. In my opinion, your account and that of Miss Bravo[6] were the best.

I hope you are back home safely in Vienna, and I am happy to have seen you again in good health and very active as always. I tried to get some news from Mursia about the translation of People in Auschwitz, but, for now, without any results: I will keep you posted. In the meantime, I warmly shake your hand.

Turin, 31 Oct. 1983[1]

Cher Hermann,

comme je te l’avais promis, je t’envoie ici mes observations sur le chapitre «Die zwei Giftgase», p. 281 suiv. du livre que tu m’as donné.[2]

1) A p. 282 et 283 il est question d’ «einen reizerzeugenden (…) Wasserstoff». Je crois qu’il-y-a là une erreur, puisque l’hydrogène (=Wasserstoff) a des propriétés tout à fait différentes, et qu’on devrait lire Warnstoff.[3] En effet, dans un livre que j’avais lu autrefois (D. Meyer, Der Gaskampf und die chemische Kampfstoffe, 1926) je trouve que le Zyklon B était (ou est?) un mélange d’acide cyanidrique (=Cyanwasserstoff) avec env. 10% «de produits alogénés du type du chloro- et bromocarbonate de méthyle et d’éthyle», dont la fonction est de signaler par leur odeur, qui est très forte et irritante, des fuites eventuelles du produit. A ce propos, je ne comprends pas bien le terme «bewahrt» (p. 282, avant-dernière ligne): on devrait lire quelque chose comme «renforce, intensifie».

2) Le terme «Schwefeläther» (p. 283) est périmé depuis longtemps: il faudrait lui substituer «Äthyläther».[4] Le raisonnement qui suit n’est pas correct, puisq’il dépend de l’échelle thermométrique qu’on a choisi (on trouverait, par exemple, 111 dégrés au lieu de 132 si on employait la température absolue); mieux éviter la quantification, et se borner à dire que la surface du corps humain est toujours bien plus haute du point d’ébullition de l’acide cyanhydrique. En tout cas, le point n’est pas essentiel, et les «faurissoniens»[5] ont tort d’insister là dessus: la tension de vapeur (Dampfdruck) de l’a. cy. est déja très forte à la température ordinaire. À Monowitz (et sans doute à Auschwitz I aussi) on employait le Zyklon B pour tuer les poux dans les blocks, même en hiver.

3) À p. 285, le passage depuis «Unter diesen Vermittlern…» jusq’à «mit dem Ausdruck „Cytochromo-oxydase“» n’est pas clair, et on dirait que quelque chose manque: mais, n’étant pas un physiologiste, je n’ose faire des corrections.

4) Dans tout le chapitre, les formules chimiques sont écrites suivant l’usage français et pas l’allemand (et italien). On devrait lire HCN au lieu de CNH, KCN et NaCN au lieu de CNK et CNNa; en particulier, la réaction de p. 286 (en bas) devrait être écrite comme suit:

Ca (CN)₂ + 2H₂O > 2HCN + Ca(OH)₂

c’est à dire, avec les petits numéros en bas et la flèche au lieu du signe =.

C’est tout. Je suis sur que tu comprendras les raison de ma méticulosité: c’est que nos adversaires sont méticuleux, ne desarment pas, et que face à eux il ne serait pas agréable d’être pris au dépourvu, ou même de devoir subir leur critiques.

J’espère que tu auras été satisfait du Congrès. Je n’ai pas beaucoup d’expérience en fait de congrès, mais mon impression est que tout a assez bien marché, sans trop de rhétorique ni de repétitions. À mon avis, ta rélation et celle de Mlle Bravo[6] ont été les meilleures.

Je t’espère bien rentré à Vienne, et je suis heureux de t’avoir revu en bonne santé et en pleine activité comme toujours. J’ai essayé d’obtenir de Mursia quelques nouvelles sur la traduction de Menschen in Auschwitz, mais, pour le moment, sans résultat: je te tiendrai au courant. Entre temps, je te serre bien cordialment la main.

Turin, Oct. 31, 1983[1]

Dear Hermann,

As I promised, I am sending you here my observations on the chapter “Die zwei Giftgase,” p. 281 ff. of the book you gave me.[2]

1) Pp. 282 and 283 discuss “einen reizerzeugenden (…) Wasserstoff.” I think that there is an error, because hydrogen (=Wasserstoff) has completely different properties, and that it should read Warnstoff.[3] In fact, in a book that I read in the past (D. Meyer, Der Gaskampf und die chemische Kampfstoffe, 1926) I find that Zyklon B was (or is?) a mixture of hydrogen cyanide (=Cyanwasserstoff) with approx. 10% “of halogenated products of the methyl- and ethyl- chloro- and bromocarbonates type,” whose function is to indicate by their odor, which is very strong and irritating, possible leaks of the product. Regarding this, I do not quite understand the term “protect” (p. 282, next-to-last line): it should read something like “strengthens, intensifies.”

2) The term “Schwefeläther” (p. 283) has been out of date for a long time: it should be replaced with “Äthyläther.”[4] The reasoning that follows is not correct, because it depends on the thermometric scale that has been chosen (for example, we would find 111 degrees instead of 132 if we used absolute temperature); better to avoid quantification, and simply say that the surface of the human body is always much higher than the boiling point of hydrogen cyanide. In any case, the point is not essential, and the “Faurissonians”[5] are wrong to insist on it: the vapor pressure (Dampfdruck) of hy. cy. is already quite high at ordinary temperatures. At Monowitz (and surely at Au. I also) they used Zyklon B to kill lice in the blocks, even in winter.

3) On p. 285, the passage from   is not clear, and it seems as if something is missing: but, not being a physiologist, I’m wary of making any corrections.

4) In the entire chapter, the chemical formulas are written following French usage, not German (and Italian). It should read HCN instead of CNH, KCN and NaCN instead of CNK and CNNa; in particular, the reaction on p. 286 (bottom) should be written as follows:

Ca (CN)₂ + 2H₂O > 2HCN + Ca(OH)₂

i.e., with the little numbers at the bottom and an arrow instead of the = sign.

That is all. I am sure you will understand the reason for my meticulousness: it is because our adversaries are meticulous and do not give up the fight, and when facing them it would not be pleasant to be taken by surprise, or even to have to endure their criticism.

I hope you are satisfied with the Conference. I do not have a great deal of experience with conferences, but my impression is that everything went quite well, without too much rhetoric or too many repetitions. In my opinion, your account and that of Miss Bravo[6] were the best.

I hope you are back home safely in Vienna, and I am happy to have seen you again in good health and very active as always. I tried to get some news from Mursia about the translation of People in Auschwitz, but, for now, without any results: I will keep you posted. In the meantime, I warmly shake your hand.